CECS 130 EXAM 1

 int main() { printf (“%c %c \n", 'a', 65); printf ("%d %ld\n", 1977, L); printf (" %10d \n", 1977); printf ("%010d \n", 1977); printf ("floats: %4.2f \n", ); printf ("%s \n", "A string"); return 0; } }

printf (“%c %c \n", 'a', 65); aA printf ("%d %ld\n", 1977, L); printf (" %10d \n", 1977); 1977 printf ("%010d \n", 1977); printf ("floats: %4.2f \n", ); 3.14 printf ("%s \n", "A string"); A string

 What’s the syntax of  While(){}  Do{} While()  What’s the difference between While and Do{} While()?

 while ( condition ) { Code to execute while the condition is true }  do { } while ( condition );  Do{ } while() executes code at least once!

 Use when the number of iterations is already known  Syntax: for ( variable initialization ; condition ; variable increment/decrement ) { Code to execute while the condition is true }

#include int main() { int x; for ( x = 0; x < 10; x++ ){ printf( "%d\n", x ); } getchar(); }

 Write a program using a FOR Loop to display all of the multiples of 5 from 0 to 100.

#include int main() { int x; for ( x = 0; x < =20; x++ ) { printf( "%d\n", x*5 ); } getchar(); }

 Use to manipulate flow in loops  What does a break statement do when executed within a loop?  What does a Continue statement do when executed within a loop?

#include main() { int x; for ( x = 10; x >5; x-- ) { if (x==7) break; } printf( “\n %d \n ”, x ); } #include main() { int x; for ( x = 10; x >5; x-- ) { if (x==7) continue; printf( “\n %d \n ”, x ); }

 Function Prototype Syntax return-type function_name ( arg_type arg1,..., arg_type argN)  Function Prototypes tell you the data type returned by the function, the data type of parameters, how many parameters, and the order of parameters  Function definitions implement the function prototype  Where are function prototypes located in the program?  Where do you find function definitions?

 Where are function prototypes located in the program?  Answer: before the main(){} function!  Function Definitions are self contained outside of the main(){} function

#include int mult ( int x, int y ); int main() { int x = 0; int y = 0; printf( "Please input two numbers to be multiplied: " ); scanf( "%d", &x ); printf( "%d ", x ); scanf( "%d", &y ); printf( "%d ", y); printf( "The product of your two numbers is %d\n", mult( x, y ) ); getchar(); } int mult (int x, int y) { return x * y; }

#include Void printReportHeader(); main() { printReportHeader; } void printReportHeader() { printf(“\n Column1\tColumn2\tColumn3\tColumn4 \n”) }

#include void printNumbers(); int iNumber = 0; main() { int x; for(x=0, x<10,x++) { printf(“\n Enter a number:”); scanf(“%d”, &iNumber); printNumbers(); } void printNumbers() { printf(“\n Your number is: %d \n”, iNumber); }

 Variable scope defines the lifetime of a variable  Local Scope: defined within functions and loses scope after function is finished. Can reuse in other functions (ex. p.123)  Global Scope: defined outside of functions and can be accessed by multiple functions

 Can you declare a one-dimensional array made up of 10 integers?  Answer: int iArray[10]  How to declare an Array  int iArray[10];  float fAverages[30];  double dResults[3];  short sSalaries [9];  char cName[19]; 18 characters and 1 null character

 Why do we initialize? Because memory spaces may not be cleared from previous values when arrays are created  Can initialize an array directly  Example int iArray[5]={0,1,2,3,4};  Can initialize an array with a loop such as FOR()

#include main() { int x; int iArray[5]; for( x=0; x < 5 ; x++) { iArray[x] = 0; }

 Can you add code to print out the values of the program below? #include main() { int x; int iArray[5]; for( x=0; x < 5 ; x++) { iArray[x] = 0; }

#include main() { int x; int iArray[5]; for( x=0; x < 5 ; x++) { iArray[x] = 0; } for(x=0 ; x<5; x++) { printf(“\n The value of iArray index %d is %d \n”, x, iArray[x]); }

 How do you search through an array?

#include main() { int x; int iValue; int iFound = -1; int iArray[5]; for( x=0; x < 5 ; x++) iArray[x] = (x+x); printf(“\n Enter value to search for:”); scanf(“%d”, &iValue); for(x=0 ; x<5; x++) { if( iArray[x] ==iValue) { iFound =x; break; } if(iFound >-1) printf(“\n I found your search value in element %d \n”, iFound); else printf(“\n Sorry, your search value was not found \n”); }

#include main() { char *str1 = “Michael”; char str2[] = “Vine”; printf(“\nThe length of string 1 is %d \n”, strlen(str1)); printf(“The length of string 2 is %d\n”, strlen(str2)); }

#include void convertL(char *); main() { char name1[] = “Michael”; convertL(name1); } void convertL(char *str) { int x; for ( x = 0; x <=strlen(str) ; x++) str[x] = tolower(str[x]); printf(“\nThe name converted to lower case is %s\n”, str); }

EntityDescription Bit Binary digit, 0 or 1Smallest value in a data file Byte Eight bitsStores a single character FieldGrouping of bytesi.e a word, social security number RecordGrouping of fieldsa single row of information, student name, age, ID, GPA FileGrouping of recordsseparate fields in a record using spaces, tabs, or commas

Kelly11/12/866Louisville Allen04/05/7749Atlanta Chelsea03/30/9012Charleston How many fields are there? How many records are there? How many bytes are there in the first record? How many bits are there in “Kelly”? How many fields are there? How many records are there? How many bytes are there in the first record? How many bits are there in “Kelly”?

Do you know the syntax for each of these, used to read and write to data files?  Pointers: think of it as the memory address of the file  fopen()  fclose()  fscanf()  fprintf()

 fopen() returns a FILE pointer back to the pRead variable #include main() { FILE *pRead; pRead = fopen(“file1.dat”, “r”); if(pRead == NULL) printf(“\nFile cannot be opened\n”); else printf(“\nFile opened for reading\n”); }

 Pretty basic.

 Reads a single field from a data file  “%s” will read a series of characters until a white space is found  can do fscanf(pRead, “%s%s”, name, hobby);

#include main() { FILE *pRead; char name[10]; pRead = fopen(“names.dat”, “r”); if( pRead == NULL ) printf( “\nFile cannot be opened\n”); else printf(“\nContents of names.dat\n”); fscanf( pRead, “%s”, name ); while( !feof(pRead) ) { printf( “%s\n”, name ); fscanf( pRead, “%s”, name ); }

Kelly11/12/866Louisville Allen04/05/7749Atlanta Chelsea03/30/9012Charleston Can you write a program that prints out the contents of this information.dat file?

#include main() { FILE *pRead; char name[10]; char birthdate[9]; float number; char hometown[20]; pRead = fopen(“information.dat”, “r”); if( pRead == NULL ) printf( “\nFile cannot be opened\n”); else fscanf( pRead, “%s%s%f%s”, name, birthdate, &number, hometown ); while( !feof(pRead) ) { printf( “%s \t %s \t %f \t %s\n”, name, birthdate, number, hometown ); fscanf( pRead, “%s%s%f%s”, name, birthdate, &number, hometown ); }

 The fprintf() function sends information (the arguments) according to the specified format to the file indicated by stream. fprintf() works just like printf() as far as the format goes. printf()

#include main() { FILE *pWrite; char fName[20]; char lName [20]; float gpa; pWrite = fopen(“students.dat”,”w”); if( pWrite == NULL ) printf(“\nFile not opened\n”); else { printf(“\nEnter first name, last name, and GPA separated” printf(“Enter data separated by spaces:”); scanf(“%s%s%f”, fName, lName, &gpa); fprintf(pWrite, “%s \t %s \t %.2f \n”, fName, lName, gpa); fclose(pWrite); }