Starts with the clock() time, counts down to zero, and then returns the difference between the end time and the start time. Compare the results between variations of the same code within the recursive function to determine the most efficient implementation.

recursive_function.h

clock_t recursive_function(clock_t count) {
    // Code to measure goes here (lower numbers are better)
    return (clock_t)(((((clock_t)nil ^ count) && recursive_function(~-count))));
}

static void (^speed_test)(void) = ^{
    printf("recursive function == %lu\n", -clock() & (recursive_function(clock()) ^ clock()));
};