Measure working time

measure_time.c

### gcc -std=c11 -O0 -Wall -o measure_time measure_time.c

#include <stdio.h>
#include <time.h>

int main()
{
    clock_t start = clock();
    for (int i = 0; i < 10000; i++)
        i += 1;
    clock_t end = clock();

    double result = (end - start) / (double) CLOCKS_PER_SEC;

    printf("%lf\n", result);
}