1. C Program Design Introduction to C Programming 主講人：虞台文

2. Content Background Main Parts of C Programs 標準輸出入裝置與輸出入函式 標準輸出入函式 算術運算子 (Arithmetic Operators ) 關係運算子 (Relation Operators ) 邏輯運算子 (Logical Operators) 巨集  The #define Preprocessor

3. C Program Design Introduction to C Programming Background

4. The C Language Currently, the most commonly-used language for embedded systems – High-level assembly Very portable – compilers exist for virtually every processor Easy-to-understand compilation Produces efficient code Fairly concise

5. C History Developed between 1969 and 1973 along with Unix Due mostly to Dennis Ritchie Designed for systems programming – Operating systems – Utility programs – Compilers – Filters Evolved from B, which evolved from BCPL The Development of the C Language

6. Computer Architecture ALU Control CPU Input Output Memory Input Device Output Device

7. C Program Design Introduction to C Programming Main Parts of C Programs

8. Our First C Program  Hello World

9. /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); }

10. The #include Directive /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } include information about standard library

11. The #include Directive /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } include information about standard library

12. Entry Point of C Programs /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } define a function called main that receives no argument define a function called main that receives no argument Function body

13. Function Body /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } Function body Function body starts with { Function body ends with }

14. C Statements /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } a C statement C statements end with ;

15. Comments /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } /*... */ or // for multiple lines (c++) for single line

16. Comments /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } /* Hello.c Our first program */ #include /* function main begins program execution */ main() { printf("hello, world\n"); } /*... */ or // for multiple lines (c++) for single line // Hello.c // Our first program #include // function main begins program execution main() { printf("hello, world\n"); } // Hello.c // Our first program #include // function main begins program execution main() { printf("hello, world\n"); }

17. // Hello.c // Our first program #include // function main begins program execution main() { printf("hello, world\n"); } // Hello.c // Our first program #include <stdio.h> // function main begins program execution main() { printf("hello, world\n"); } printf  Print formatted data to stdout function name function Parameter (string)

18. printf  Print formatted data to stdout printf("Hello, World\n"); – Instructs computer to perform an action Specifically, prints the string of characters within quotes ( " " ) – Entire line called a statement All statements must end with a semicolon ( ; ) – Escape character ( \ ) Indicates that printf should do something out of the ordinary \n is the newline character

19. Some Common Escape Sequences

20. Editing  Compiling  Linking  Execution Ctrl-Z (EOF)

21. Editing  Compiling  Linking  Execution

22. 練習 1. 重複以上 Editing  Compiling  Linking  Execution 之過程 2. 修改 Hello.c 程式，練習不同的 Escape Sequences ，如： – printf("Hello,\nWorld\n"); – printf("Hello,\a\a\a\a\a\aWorld\n"); – printf("Hello,\b\b\b\b\b\bWorld\n"); – printf("Hello,\tWorld\n");

23. 練習 3. 作業題 4. 在 IDE 環境下重做以上各練習

24. C Program Design Introduction to C Programming 標準輸出入裝置 與輸出入函式

25. 標準輸出入裝置 ALU Control CPU Input Output Memory Input Device Output Device Input Output 預設

26. 標準輸出入裝置之重新導向 標準輸出裝置重新導向 : > outfile 標準輸出裝置重新導向 : > outfile

27. 標準輸出入裝置之重新導向 標準輸出裝置重新導向 : > outfile 標準輸出裝置重新導向 : > outfile

28. 標準輸出入裝置之重新導向 標準輸出裝置重新導向 : > outfile 標準輸出裝置重新導向 : > outfile

29. C Program Design Introduction to C Programming 標準輸出入函式

30. printf  Print formatted data to stdout

31. scanf  Read formatted data from stdin

32. Add Two Integers 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ integer1 integer2 sum = integer1 + integer2

33. Add Two Integers 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ 1/* AddTwoInts.c 2 Addition program */ 3#include <stdio.h> 4 5/* function main begins program execution */ 6main() 7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ integer1 integer2 sum Enter first integer 15 15 Enter second integer 20 20 35 Sum is 35 >

34. 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ 標準輸出入裝置之重新導向 標準輸出裝置重新導向 : > Outfile 標準輸入裝置重新導向 : < Infile 標準輸出裝置重新導向 : > Outfile 標準輸入裝置重新導向 : < Infile integer1 integer2 sum 15 20 35

35. 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ 標準輸出入裝置之重新導向 標準輸出裝置重新導向 : > Outfile 標準輸入裝置重新導向 : < Infile 標準輸出裝置重新導向 : > Outfile 標準輸入裝置重新導向 : < Infile integer1 integer2 sum 15 20 35

36. 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ 標準輸出入裝置之重新導向 標準輸出裝置重新導向 : > Outfile 標準輸入裝置重新導向 : < Infile 標準輸出裝置重新導向 : > Outfile 標準輸入裝置重新導向 : < Infile integer1 integer2 sum 15 20 35

37. Definition of Variables 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ C 語言中任何變數使用前均需宣告或定義 變數名稱必需是一有效的 identifier 區分大小寫 (case sensitive) ，例 A1 與 a1 不為同一變數 變數之資料型態 ( int, char, float, double, … ) 變數之位址與值 C 語言中任何變數使用前均需宣告或定義 變數名稱必需是一有效的 identifier 區分大小寫 (case sensitive) ，例 A1 與 a1 不為同一變數 變數之資料型態 ( int, char, float, double, … ) 變數之位址與值 integer1 integer2 sum 15 20 35

38. 變數定義之注意事項 定義意義明確之變數名稱 – 勿擔心變數長度過長 ( 有效長度至少 31) – 定義名稱不得為 C 語言之保留字 範例： 變數未設定其值前，勿任意假設其初值 // Single declarations int age; float amountOfMoney; char initial; // Single declarations int age; float amountOfMoney; char initial; // Multiple declarations int age, houseNumber, quantity; float distance, rateOfDiscount; char firstInitial, secondInitial; // Multiple declarations int age, houseNumber, quantity; float distance, rateOfDiscount; char firstInitial, secondInitial;

39. Single vs. Multiple Declarations 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ int integer1; int integer2; int sum; int integer1, integer2, sum; 

40. 變數之初值 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ integer1 integer2 sum ? ? ?

41. 變數之初值 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ 1/* AddTwoInts.c 2 Addition program */ 3#include 4 5/* function main begins program execution */ 6main() 7{7{ 8 int integer1; /* first number to be input by user */ 9 int integer2; /* second number to be input by user */ 10 int sum; /* variable in which sum will be stored */ 11 12 printf( "Enter first integer\n" ); /* prompt */ 13 scanf( "%d", &integer1 ); /* read an integer */ 14 15 printf( "Enter second integer\n" ); /* prompt */ 16 scanf( "%d", &integer2 ); /* read an integer */ 17 18 sum = integer1 + integer2; /* assign total to sum */ 19 20 printf( "Sum is %d\n", sum ); /* print sum */ 21} /* end function main */ integer1 integer2 sum ? ? ? 變數未設定其值前，勿任意假設其初值

42. Basic Data Types char a single byte, capable of holding one character in the local character set int an integer, typically reflecting the natural size of integers on the host machine float single-precision floating point double double-precision floating point The type of an object determines the set of values it can have and what operations can be performed on it.

43. Program Indentation /* AddTwoInts.c Addition program */ #include /* function main begins program execution */ main() { int integer1; /* first number to be input by user */ int integer2; /* second number to be input by user */ int sum; /* variable in which sum will be stored */ printf( "Enter first integer\n" ); /* prompt */ scanf( "%d", &integer1 ); /* read an integer */ printf( "Enter second integer\n" ); /* prompt */ scanf( "%d", &integer2 ); /* read an integer */ sum = integer1 + integer2; /* assign total to sum */ printf( "Sum is %d\n", sum ); /* print sum */ } /* end function main */ /* AddTwoInts.c Addition program */ #include /* function main begins program execution */ main() { int integer1; /* first number to be input by user */ int integer2; /* second number to be input by user */ int sum; /* variable in which sum will be stored */ printf( "Enter first integer\n" ); /* prompt */ scanf( "%d", &integer1 ); /* read an integer */ printf( "Enter second integer\n" ); /* prompt */ scanf( "%d", &integer2 ); /* read an integer */ sum = integer1 + integer2; /* assign total to sum */ printf( "Sum is %d\n", sum ); /* print sum */ } /* end function main */ Tab

44. Bad Format (I) /* AddTwoInts.c Addition program */ #include /* function main begins program execution */ main() { int integer1; /* first number to be input by user */ int integer2; /* second number to be input by user */ int sum; /* variable in which sum will be stored */ printf( "Enter first integer\n" ); /* prompt */ scanf( "%d", &integer1 ); /* read an integer */ printf( "Enter second integer\n" ); /* prompt */ scanf( "%d", &integer2 ); /* read an integer */ sum = integer1 + integer2; /* assign total to sum */ printf( "Sum is %d\n", sum ); /* print sum */ } /* end function main */ /* AddTwoInts.c Addition program */ #include /* function main begins program execution */ main() { int integer1; /* first number to be input by user */ int integer2; /* second number to be input by user */ int sum; /* variable in which sum will be stored */ printf( "Enter first integer\n" ); /* prompt */ scanf( "%d", &integer1 ); /* read an integer */ printf( "Enter second integer\n" ); /* prompt */ scanf( "%d", &integer2 ); /* read an integer */ sum = integer1 + integer2; /* assign total to sum */ printf( "Sum is %d\n", sum ); /* print sum */ } /* end function main */ 以下範例編譯後產生相同結果，但不易閱讀

45. Bad Format (II) /* AddTwoInts.c Addition program */ #include /* function main begins program execution */ main(){ int integer1; /* first number to be input by user */ int integer2; /* second number to be input by user */ int sum; /* variable in which sum will be stored */ printf( "Enter first integer\n" ); /* prompt */ scanf( "%d", &integer1 ); /* read an integer */ printf( "Enter second integer\n" ); /* prompt */ scanf( "%d", &integer2 ); /* read an integer */ sum = integer1 + integer2; /* assign total to sum */ printf( "Sum is %d\n", sum ); /* print sum */ } /* end function main */ /* AddTwoInts.c Addition program */ #include /* function main begins program execution */ main(){ int integer1; /* first number to be input by user */ int integer2; /* second number to be input by user */ int sum; /* variable in which sum will be stored */ printf( "Enter first integer\n" ); /* prompt */ scanf( "%d", &integer1 ); /* read an integer */ printf( "Enter second integer\n" ); /* prompt */ scanf( "%d", &integer2 ); /* read an integer */ sum = integer1 + integer2; /* assign total to sum */ printf( "Sum is %d\n", sum ); /* print sum */ } /* end function main */ 以下範例編譯後產生相同結果，但不易閱讀

46. 練習 #include main() { int sum; float money; char letter; double pi; sum = 10;/* assign integer value */ money = 2.21;/* assign float value */ letter = 'A';/* assign character value */ pi = 2.01E6;/* assign a double value */ printf("value of sum = %d\n", sum ); printf("value of money = %f\n", money ); printf("value of letter = %c\n", letter ); printf("value of pi = %e\n", pi ); } #include main() { int sum; float money; char letter; double pi; sum = 10;/* assign integer value */ money = 2.21;/* assign float value */ letter = 'A';/* assign character value */ pi = 2.01E6;/* assign a double value */ printf("value of sum = %d\n", sum ); printf("value of money = %f\n", money ); printf("value of letter = %c\n", letter ); printf("value of pi = %e\n", pi ); } 1. 實作以下程式，預測及觀察其結果 2. 將變數值改以呼叫 scanf() 方式要求使用 者輸入 3. 輸出入重新導向練習

47. C Program Design Introduction to C Programming 算術運算子 (Arithmetic Operators)

48. Arithmetic Operators

49. Precedence of Arithmetic Operators

50. 範例 : y = 2x 2 +3x+7 /* PolynormialEval.c */ #include main() { int x, y; printf("x = ");/* prompt */ scanf( "%d", &x ); /* read x */ /* Evaluate y = 2x^2 + 3x + 7 */ y = 2 * x * x + 3 * x + 7; /* print y */ printf( "y = 2 * %d * %d + 3 * %d + 7 = %d\n", x, x, x, y); } /* PolynormialEval.c */ #include main() { int x, y; printf("x = ");/* prompt */ scanf( "%d", &x ); /* read x */ /* Evaluate y = 2x^2 + 3x + 7 */ y = 2 * x * x + 3 * x + 7; /* print y */ printf( "y = 2 * %d * %d + 3 * %d + 7 = %d\n", x, x, x, y); } y = 2 * x * x + 3 * x + 7;

51. 範例 : y = 2x 2 +3x+7 y = 2 * x * x + 3 * x + 7;

52. C Program Design Introduction to C Programming 關係運算子 (Relation Operators)

53. Relation Operators in C The result of a relation operation is true (nonzero) or false (zero).

54. Statements Simple Statements lower = 0; upper = 300; step = 20; fahr = lower; Null Statement ; // a null statement Compound Statements (block statements) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; } 4 simple statements 1 compound statement

55. If-Else Statement if (expression) statement 1 else statement 2

56. If-Else Statement if (expression) statement 1 else statement 2 expression If expression is evaluated to true (nonzero), statement 1 is executed; otherwise, statement 2 is executed. If expression is evaluated to true (nonzero), statement 1 is executed; otherwise, statement 2 is executed. start end expression statement 1 statement 2 truefalse

57. If-Else Statement if (expression) statement 1 else statement 2 expression start end expression statement 1 statement 2 truefalse option

58. If- Statement if (expression) statement expression start end expression statement true false

59. 範例 : Decision Making (I) /* pass1.c */ #include main() { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold){ printf("Incredible, you passed with a merit\n"); } /* pass1.c */ #include main() { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold){ printf("Incredible, you passed with a merit\n"); } }

60. Program Indentation /* pass1.c */ #include main() { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold){ printf("Incredible, you passed with a merit\n"); } /* pass1.c */ #include main() { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold){ printf("Incredible, you passed with a merit\n"); }

61. Simplification /* pass1.c */ #include main() { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold){ printf("Incredible, you passed with a merit\n"); } /* pass1.c */ #include main() { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold){ printf("Incredible, you passed with a merit\n"); }  

62. Simplification /* pass1.c */ #include main() { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold) printf("Incredible, you passed with a merit\n"); } /* pass1.c */ #include main() { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold) printf("Incredible, you passed with a merit\n"); }

63. 範例 : Decision Making (II) /* pass2.c */ #include main(void) { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold){ printf("Incredible, you passed with a merit\n"); } else{ printf("You failed, unlucky\n"); } /* pass2.c */ #include main(void) { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold){ printf("Incredible, you passed with a merit\n"); } else{ printf("You failed, unlucky\n"); } }

64. Program Indentation /* pass2.c */ #include main(void) { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold){ printf("Incredible, you passed with a merit\n"); } else{ printf("You failed, unlucky\n"); } /* pass2.c */ #include main(void) { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold){ printf("Incredible, you passed with a merit\n"); } else{ printf("You failed, unlucky\n"); }

65. Simplification /* pass2.c */ #include main(void) { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold){ printf("Incredible, you passed with a merit\n"); } else{ printf("You failed, unlucky\n"); } /* pass2.c */ #include main(void) { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold){ printf("Incredible, you passed with a merit\n"); } else{ printf("You failed, unlucky\n"); }    

66. Simplification /* pass1.c */ #include main(void) { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold) printf("Incredible, you passed with a merit\n"); else printf("You failed, unlucky\n"); } /* pass1.c */ #include main(void) { int threshold = 75; int score; printf("Enter your score, please\n"); scanf("%d",&score); if (score >= threshold) printf("Incredible, you passed with a merit\n"); else printf("You failed, unlucky\n"); }

67. While- Statement while(expression) statement expression start end expression statement true false

68. 範例：華氏  攝氏

69. #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; }

70. 範例：華氏  攝氏 #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } }

71. 範例：華氏  攝氏 #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; }

72. #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } Integer Arithmetic

73. #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } Integer Arithmetic Can it be “ celsius = 5/9*(fahr-32); ”? Why? Can it be “ celsius = 5/9*(fahr-32); ”? Why?

74. printf  General-Purpose Output Formatting Function #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } }

75. printf  General-Purpose Output Formatting Function printf("%d\t%d\n", fahr, celsius); format string decimaltabdecimalnewline

76. printf  General-Purpose Output Formatting Function #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } } Left aligned

77. printf  General-Purpose Output Formatting Function #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } } printf("%3d %6d\n", fahr, celsius);

78. printf  General-Purpose Output Formatting Function #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { int fahr, celsius; int lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d\t%d\n", fahr, celsius); fahr = fahr + step; } printf("%3d %6d\n", fahr, celsius); Right aligned

79. 範例：華氏  攝氏 ( 浮點 ) #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { float fahr, celsius; float lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { float fahr, celsius; float lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; } }

80. 範例：華氏  攝氏 ( 浮點 ) #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { float fahr, celsius; float lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; } #include <stdio.h> /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { float fahr, celsius; float lower, upper, step; lower = 0;/* lower limit of temperature scale */ upper = 300;/* upper limit */ step = 20;/* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; } }

81. 範例：華氏  攝氏 ( 浮點 ) #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { float fahr, celsius; float lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { float fahr, celsius; float lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; }

82. More on printf

83. Program Indentation #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { float fahr, celsius; float lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { float fahr, celsius; float lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; }

84. Program Indentation #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { float fahr, celsius; float lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { float fahr, celsius; float lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; } Statement

85. Program Indentation #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { float fahr, celsius; float lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { float fahr, celsius; float lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; } Statement

86. Program Indentation #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { float fahr, celsius; float lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; } #include /* print Fahrenheit-Celsius table for fahr = 0, 20,..., 300 */ main() { float fahr, celsius; float lower, upper, step; lower = 0; /* lower limit of temperature scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f\n", fahr, celsius); fahr = fahr + step; } Statement Compound Statement

87. 練習 1. Using 2. Redo the same task but with the starting number, ending number, and step being given by a user.

88. 練習 3. Write a C program which asks a user to input a positive integer. The program then reports the minimum factor of that number in 2, 3, 5, 7, 11 if available. Otherwise, reports “fail to find any factor in 2, 3, 5, 7, 11.” 4. The same as above, but the program reports all factors of that number in 2, 3, 5, 7, 11. 5. The same as above, but the program reports all possible factors of that number.

89. C Program Design Introduction to C Programming 邏輯運算子 (Logical Operators)

90. Logical Operators && ( logical AND ) – Returns true if both conditions are true || ( logical OR ) – Returns true if either of its conditions are true ! ( logical NOT, logical negation ) – Reverses the truth/falsity of its condition – Unary operator, has one operand

91. Truth Tables

92. Examples if((celsius >= 25.0) && (celsius <= 28.0)) printf("It is very comfortable\n"); if((celsius >= 25.0) && (celsius <= 28.0)) printf("It is very comfortable\n"); if((celsius 32.0)) printf("It is bad\n"); else printf("It is comfortable\n"); if((celsius 32.0)) printf("It is bad\n"); else printf("It is comfortable\n"); if(!(celsius <= 18.0)) printf("It is not very cold\n"); else printf("It is better to take a jacket\n"); if(!(celsius <= 18.0)) printf("It is not very cold\n"); else printf("It is better to take a jacket\n");

93. 注意事項 int total, count;......... if(total / count >= 60) printf("Passed\n"); else printf("Failed\n"); int total, count;......... if(total / count >= 60) printf("Passed\n"); else printf("Failed\n"); count 若為零將產生 divide by zero 之 exception.

94. 注意事項 int total, count;......... if(total / count >= 60) printf("Passed\n"); else printf("Failed\n"); int total, count;......... if(total / count >= 60) printf("Passed\n"); else printf("Failed\n"); int total, count;......... if(total / count >= 60 && count > 0) printf("Passed\n"); else printf("Failed\n"); int total, count;......... if(total / count >= 60 && count > 0) printf("Passed\n"); else printf("Failed\n"); int total, count;......... if(count > 0 && total / count >= 60) printf("Passed\n"); else printf("Failed\n"); int total, count;......... if(count > 0 && total / count >= 60) printf("Passed\n"); else printf("Failed\n"); Why?

95. 注意事項 int total, count;......... if(total / count >= 60) printf("Passed\n"); else printf("Failed\n"); int total, count;......... if(total / count >= 60) printf("Passed\n"); else printf("Failed\n"); int total, count;......... if(total / count < 60 || count == 0) printf("Failed\n"); else printf("Passed\n"); int total, count;......... if(total / count < 60 || count == 0) printf("Failed\n"); else printf("Passed\n"); int total, count;......... if(count == 0 || total / count < 60) printf("Failed\n"); else printf("Passed\n"); int total, count;......... if(count == 0 || total / count < 60) printf("Failed\n"); else printf("Passed\n"); Why?

96. 練習 main() { int x=1,y=2,z=3; int p,q; p = (x>y) && (z<y); /* False i.e. 0 */ q = (y>x) || (y>z); /* True i.e. 1 */ printf(" %d && %d = %d\n",p,q,p&&q); printf(" %d || %d = %d\n",p,q,p||q); /* Can mix "logical" values and arithmetic */ printf(" %d && %d = %d\n",x,q,x&&q); printf(" %d || %d = %d\n",p,y,p||y); /* Exercise the NOT operator */ printf(" ! %d = %d\n",p,!p); printf(" ! %d = %d\n",q,!q); /* NOT operator applied to arithmetic */ printf(" ! %d = %d\n",z,!z); } main() { int x=1,y=2,z=3; int p,q; p = (x>y) && (z<y); /* False i.e. 0 */ q = (y>x) || (y>z); /* True i.e. 1 */ printf(" %d && %d = %d\n",p,q,p&&q); printf(" %d || %d = %d\n",p,q,p||q); /* Can mix "logical" values and arithmetic */ printf(" %d && %d = %d\n",x,q,x&&q); printf(" %d || %d = %d\n",p,y,p||y); /* Exercise the NOT operator */ printf(" ! %d = %d\n",p,!p); printf(" ! %d = %d\n",q,!q); /* NOT operator applied to arithmetic */ printf(" ! %d = %d\n",z,!z); } 1. 預測以下程式將產生何種結果 2. 實作以下程式視預測是否正確

97. C Program Design Introduction to C Programming 巨集 The #define Preprocessor

98. #define #include #define PI 3.14159 main() { double radius; printf("Enter the radius of a circle:"); scanf("%lf", &radius); printf("The perimeter of the circle: %lf\n", 2.0 * PI * radius); printf("The area of the circle: %lf\n", PI * radius * radius); } #include <stdio.h> #define PI 3.14159 main() { double radius; printf("Enter the radius of a circle:"); scanf("%lf", &radius); printf("The perimeter of the circle: %lf\n", 2.0 * PI * radius); printf("The area of the circle: %lf\n", PI * radius * radius); } for text substitution