1. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 1 Chapter 2 Elementary Programming

2. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 2 Numerical Data Types

3. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 3 sizeof Function You can use the sizeof function to find the size of a type. For example, the following statement displays the size of int, long, and double on your machine. cout << sizeof(int) << " " << sizeof(long) << " " << sizeof(double);

4. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 4 Synonymous Types short int is synonymous to short. unsigned short int is synonymous to unsigned short. long int is synonymous to long. unsigned long int is synonymous to unsigned long. For example, short int i = 2; is same as short i = 2;

5. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 5 Numeric Literals A literal is a constant value that appears directly in a program. For example, 34, 1000000, and 5.0 are literals in the following statements: int i = 34; long k = 1000000; double d = 5.0;

6. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 6 octal and hex literals To denote an octal integer literal, use a leading 0 (zero), and to denote a hexadecimal integer literal, use a leading 0x or 0X (zero x). For example, the following code displays the decimal value 65535 for hexadecimal number FFFF and decimal value 8 for octal number 10. cout << 0xFFFF << " " << 010;

7. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 7 Hexadecimal  Binary 0000 0 0 0001 1 1 0010 2 2 0011 3 3 0100 4 4 0101 5 5 0110 6 6 0111 7 7 1000 8 8 1001 9 9 1010 A 10 1011 B 11 1100 C 12 1101 D 13 1110 E 14 1111 F 15 Binary Hex Decimal To convert a hexadecimal number to a binary number, simply convert each digit in the hexadecimal number into a four-digit binary number. To convert a binary number to a hexadecimal, convert every four binary digits from right to left in the binary number into a hexadecimal number. For example, Companion Website

8. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 8 why called floating-point? The float and double types are used to represent numbers with a decimal point. Why are they called floating-point numbers? These numbers are stored into scientific notation. When a number such as 50.534e-1 is converted into scientific notation such as 5.0534, its decimal point is moved (i.e., floated) to a new position.

9. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 9 Numeric Operators

10. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 10 Integer Division +, -, *, /, and % 5 / 2 yields an integer 2. 5.0 / 2 yields a double value 2.5 5 % 2 yields 1 (the remainder of the division)

11. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 11 Remainder Operator Remainder is very useful in programming. For example, an even number % 2 is always 0 and an odd number % 2 is always 1. So you can use this property to determine whether a number is even or odd. Suppose today is Saturday and you and your friends are going to meet in 10 days. What day is in 10 days? You can find that day is Tuesday using the following expression:

12. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 12 Example: Displaying Time Write a program that obtains minutes and remaining seconds from an amount of time in seconds. #include using namespace std; int main() { int seconds = 500; int minutes = seconds / 60; int remainingSeconds = seconds % 60; cout << seconds << " seconds is " << minutes << " minutes and " << remainingSeconds << " seconds " << endl; system("PAUSE"); return 0; } DisplayTime.cpp 500 seconds is 8 minutes and 20 seconds

13. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 13 Arithmetic Expressions is translated to (3+4*x)/5 – 10*(y-5)*(a+b+c)/x + 9*(4/x + (9+x)/y)

14. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 14 Example: Converting Temperatures Write a program that converts a Fahrenheit degree to Celsius using the formula: #include using namespace std; int main() { double fahrenheit; cout << "Enter a degree in Fahrenheit: "; cin >> fahrenheit; // Enter a degree in Fahrenheit // Obtain a celsius degree double celsius = (5.0 / 9) * (fahrenheit - 32); cout << "Fahrenheit " << fahrenheit << " is " << celsius << " in Celsius" << endl; // Display result system("PAUSE"); return 0; } FahrenhetToCelsius.cpp

15. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 15 Shorthand Assignment Operators OperatorExampleEquivalent +=i += 8i = i + 8 -=f -= 8.0f = f - 8.0 *=i *= 8i = i * 8 /=i /= 8i = i / 8 %=i %= 8i = i % 8

16. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 16 Increment and Decrement Operators OperatorNameDescription ++varpreincrement The expression (++var) increments var by 1, and the new value of var is returned. var++postincrementThe expression (var++) returns the original old value, and then var is incremented by 1. --varpredecrement The expression (--var) decrements var by 1, and the new value of var is returned. var--postdecrement The expression (var--) returns the original old value, and then var is decremented by 1.

17. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 17 Increment and Decrement Operators, cont. newNum becomes 100 newNum becomes 110

18. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 18 Increment and Decrement Operators, cont. double x=1.0; double y=5.0; double z=x-- + (++y) After all three lines are executed, y becomes 6.0 z becomes 7.0 x becomes 0.0

19. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 19 Numeric Type Conversion Consider the following statements: short i = 100; long k = i * 3 + 4; double d = i * 3.1 + k / 2;

20. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 20 Type Casting Type Casting. Converting an expression of a given type into another type. double d = 3; (widening) -------------------------------------- int i = static_cast (5.4); (narrowing) This is the same as: int i = (int)5.4;

21. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 21 NOTE Casting does not change the variable being cast. For example, d is not changed after casting in the following code: double d = 4.5; int i = static_cast (d); // d is not changed

22. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 22 Example: Keeping Two Digits After Decimal Points Write a program that displays the sales tax with two digits after the decimal point. #include using namespace std; int main() { // Enter purchase amount double purchaseAmount; cout << "Enter purchase amount: "; cin >> purchaseAmount; double tax = purchaseAmount * 0.06; cout (tax * 100) / 100.0; system("PAUSE"); return 0; } If user entered 197.55 The sales tax is 6% of purchase Tax is 11.853 Casting statement: static_cast (tax * 100) gives 1185 So: static_cast (tax*100)/100.0 is 11.85 SalesTax.cpp

23. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 23 Character Data Type char letter = 'A'; (ASCII) char numChar = '4'; (ASCII) NOTE: The increment and decrement operators can also be used on char variables to get the next or preceding character. For example, the following statements display character b. char ch = 'a'; cout << ++ch; The character type, char, is used to represent a single letter.

24. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 24 Appendix B: ASCII Character Set ASCII (American Standard Code for Information Interchange) The size of the char type is : 1 byte. Example: the letter A has decimal equivalent 65.

25. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 25 ASCII Character Set, cont. ASCII Character Set in the hexadecimal index.

26. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 26 Read Characters To read a character from the keyboard, use cout << "Enter a character: "; char ch; cin >> ch;

27. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 27 Escape Sequences for Special Characters Example: the following statement displays a text and moves the cursor to the next line: cout<<“Welcome to C++\n”;

28. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 28 Casting between char and Numeric Types int i = ' a ' ; // Same as int i = (int) ' a ' ; cout<<i; // i is 97; char ch = 97; //Same as char ch=(char)97; Cout<<ch; // ch is a; Char ch = 65.25; Cout << ch; // ch is character A;

29. Liang, Introduction to Programming with C++, Second Edition, (c) 2010 Pearson Education, Inc. All rights reserved. 0136097200 29 Numeric Operators on Characters The char type is treated as if it is an integer of the byte size. All numeric operators can be applied to char operands. A char operand is automatically cast into a number if the other operand is a number or a character. For example, the following statements int i = '2' + '3'; // (int)'2' is 50 and (int)'3' is 51 cout << "i is " << i << endl; // i is decimal 101 int j = 2 + 'a'; // (int)'a' is 97 cout << "j is " << j << endl; cout << j << " is the ASCII code for character " << static_cast (j) << endl; Display i is 101 j is 99 99 is the ASCII code for character c