Question

I have a file stream open and ready.

How do I access and change a single Byte in the stream such that the change is reflected on the file?

Any suggestions?

Answer 1

#include "stdio.h"

int main(void)
{
    FILE* f = fopen("so-data.dat", "r+b"); // Error checking omitted
    fseek(f, 5, SEEK_SET);
    fwrite("x", 1, 1, f);
    fclose(f);
}