Direct file I/O with fwrite() and fread(). - C File

C examples for File:File Read

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Description

Direct file I/O with fwrite() and fread().

Demo Code

#include <stdlib.h>
#include <stdio.h>

#define SIZE 20/*from  w  ww.j  ava  2  s.co m*/

int main( void )
{
   int count, array1[SIZE], array2[SIZE];
   FILE *fp;

   for (count = 0; count < SIZE; count++)
       array1[count] = 2 * count;

   /* Open a binary mode file. */

   if ( (fp = fopen("direct.txt", "wb")) == NULL)
   {
       fprintf(stderr, "Error opening file.");
       exit(1);
   }
   /* Save array1[] to the file. */

   if (fwrite(array1, sizeof(int), SIZE, fp) != SIZE)
   {
       fprintf(stderr, "Error writing to file.");
       exit(1);
   }

   fclose(fp);

   /* Now open the file for reading in binary mode. */

   if ( (fp = fopen("direct.txt", "rb")) == NULL)
   {
       fprintf(stderr, "Error opening file.");
       exit(1);
   }

   /* Read the data into array2[]. */

   if (fread(array2, sizeof(int), SIZE, fp) != SIZE)
   {
       fprintf(stderr, "Error reading file.");
       exit(1);
   }

   fclose(fp);

   /* Now display both arrays to show they're the same. */

   for (count = 0; count < SIZE; count++)
       printf("%d\t%d\n", array1[count], array2[count]);

   return 0;
}

Result


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