Why C has so many different types? [closed]

Answer 1

To avoid the warnings

double mytimer(struct timeval * start, struct timeval * end) {
    long usec = end->tv_usec - start->tv_usec;
    long sec = end->tv_sec - start->tv_sec;
    return 1.0 * sec + 1e-6 * usec;
}

If you see the datatypes defined in , inherently you'll find

typedef long time_t;
...
typedef long suseconds_t;

There are no specific format specifiers for struct timeval but the structure members are of type long. Hope this solves your problem.