C/File/File fwrite fread

#include <stdio.h>
#include <stdlib.h>
int main(void)
{
  FILE *fp;
  int i;
  /* open file for output */
  if((fp = fopen("my.txt", "wb"))==NULL) {
    printf("Cannot open file.\n");
    exit(1);
  }
  i = 100;
  if(fwrite(&i, 2, 1, fp) != 1) { 
    printf("Write error occurred.\n");
    exit(1);
  }
  fclose(fp);
  /* open file for input */
  if((fp = fopen("myfile", "rb"))==NULL) {
    printf("Cannot open file.\n");
    exit(1);
  }
  if(fread(&i, 2, 1, fp) != 1) {
    printf("Read error occurred.\n");
    exit(1);
  }
  printf("i is %d", i);
  fclose(fp);
  return 0;
}