just count upto 5:
#include <stdio.h>
#include <conio.h>
#include <ctype.h>
int main()
{
int c;
int count =0;
FILE *fp;
fp = fopen("file1.txt", "r");
while (((c =fgetc(fp)) != EOF) && count <5 )
{
if (isdigit(c))
{
putchar(c);
count ++;
}
}
getch();
}