[C] Đọc giá trị từ File

#include <stdio.h>

#include <stdlib.h>

int main()

{

   int num;

   FILE *fptr;

   if ((fptr = fopen("C:\\program.txt","r")) == NULL){

       printf("Error! opening file");

       // Program exits if the file pointer returns NULL.

       exit(1);

   }

   fscanf(fptr,"%d", &num);

   printf("Value of n=%d", num);

   fclose(fptr);

   return 0;

}