cycle_between_values

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



#define     VAL_ONE             10
#define     VAL_TWO             5
#define     TOTAL_ITERATIONS    1000000

// Functional pointer
void (*with_test_pointer)(int *) = NULL;

void with_xor(int *value)
{
    *value ^= VAL_ONE ^ VAL_TWO;
}


void with_conditional(int *value)
{
    *value = (*value == VAL_ONE)? VAL_TWO : VAL_ONE;
}

void with_if(int *value)
{
    if(VAL_ONE == *value)
    {
        *value = VAL_TWO;
    }
    else
    {
        *value = VAL_ONE;
    }


}



void run_test(void (*with_test_pointer)(int*), double *time_spent)
{

    int i;
    clock_t start, end;
    int a = VAL_ONE;

    start = clock();
    for(i = 0; i < TOTAL_ITERATIONS; i++)
    {
        (*with_test_pointer)(&a);
    }
    end = clock();
    *time_spent = ((double) (end - start))/ CLOCKS_PER_SEC;

}



int main()
{

    int i;
    double diff;
    double diff_xor = 0;
    double diff_if = 0;
    double diff_conditional = 0;



    for(i = 0; i < 10; i++)
    {

        run_test(&with_xor, &diff);

        diff_xor += diff;

        run_test(&with_if, &diff);

        diff_if += diff;

        run_test(&with_conditional, &diff);

        diff_conditional += diff;


    }

    printf("xor   %f\t\t\t\n", diff_xor);

    printf("conditional   %f\t\t\t\n", diff_conditional);

    printf("if   %f\t\t\t\n", diff_if);


}