Function putw()and getw() in C

Function putw()

This function writes an integer (whole number) into a file. The prototype of the function is as shown below.

putw (Number, FILE* Stream);

The first argument is the number to be written and the second is the file pointer. The header file <stdio. h> should be included in the program. The following is an illustration of the code:

int n = 100;

FILE* Fptr;

putw( n, Fptr );

The function writes one value at a time. For a number of values to be written, the function may be called again with the help of a loop.

Function getw ()

This function reads an integer data from the file. The function may be called in the following manner:

FILE* Fptr;

getw (Fptr);

If a number of values are to be obtained we may use a loop to call the function several times.

Illustrates the application of functions putw () and getw ().

#include <stdio.h> 
 #include <stdlib.h> // for exit function 
 void main() 
 { 
   FILE* Fptr; 
   int i, j, k[6]; 
   Fptr = fopen("file1","w"); 
   clrscr(); 
   if(Fptr ==NULL) 
    { 
       printf("File could not be opened."); 
       exit (1); 
    } 
   else 
        fprintf(stdout, "File is open. Enter data.\n"); 
        for(i =0; i <6; i++) 
        putw(k[i] = 5*i, Fptr ); 
        fclose(Fptr); 
        Fptr = fopen ("file1","r"); 
        printf("The values of elements of array k are as below.\n"); 
        for (j =0; j<6; j++) 
        printf("%d\t", getw(Fptr)); 
        printf ("\n"); 
        fclose(Fptr); 
 }