Test the efficiency of recursive functions and loop constructs and conditionals

speed_test.m

#import "Clocking.h"

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

#define CONDITION(x) ((clock_t)nil ^ x)
#define DECREMENT(x) (x = ~-x)
#define ADJUST_TIME(x) x / CLOCKS_PER_SEC
#define TOTAL_TIME(a,z) ADJUST_TIME((double)(z - a))
#define PRINT_RESULT(a,z) printf("\n%lu iterations:\n\tbeg %f\n\tend %f\n\t----------------\n\tsum\t%f\n------------------------- %f\n\n", (unsigned long)a, ADJUST_TIME(a), ADJUST_TIME(z), TOTAL_TIME(a, z), (TOTAL_TIME(a, z)/a) * CLOCKS_PER_SEC)


@interface Clocking ()

@end


@implementation Clocking

- (void)clock_tests {
    [super viewDidLoad];

    {
        clock_t start_t;
        clock_t end_t =
        ({
            clock_t count = (start_t = clock());
            for (; CONDITION(count); ) {
                DECREMENT(count);
            }
            clock();
        });
        PRINT_RESULT((double)start_t, (double)end_t);
    }
    
    {
        clock_t start_t;
        clock_t end_t =
        ({
            clock_t count = (start_t = clock());
            do {
                DECREMENT(count);
            } while (CONDITION(count));
            clock();
        });
        PRINT_RESULT((double)start_t, (double)end_t);
    }
    
    {
        clock_t start_t, end_t;
        ({
            static clock_t (^recursive_f)(clock_t);
            static clock_t (^ const * recursive_t)(clock_t) = &recursive_f;
            end_t = (recursive_f = ^ (clock_t count) {
                return (CONDITION(count)) ? (*recursive_t)(DECREMENT(count)) : (clock_t)clock();
            })(({
                start_t = clock();
                start_t;
            }));
        });
        PRINT_RESULT((double)start_t, (double)end_t);
    }
}


@end

Sample console output:

161258 iterations:
beg 0.161258
end 0.161393
----------------
sum 0.000135
------------------------- 0.000837

161408 iterations:
beg 0.161408
end 0.161540
----------------
sum 0.000132
------------------------- 0.000818

161543 iterations:
beg 0.161543
end 0.162586
----------------
sum 0.001043
------------------------- 0.006456