Tempo de execução de alocações em C/C++

#include <iostream>  // cout
#include <cstdlib>  // allocs
#include <time.h>  // clock
#include <locale>  // setlocale

#define ITERACOES 1000000

int main() {
    clock_t clock1, clock2;
    char *buffer1, *buffer2;

    std::cout.precision(4);
    setlocale( LC_ALL, "");     // caracteres acentuados

    std::cout << "Resolução: " << CLOCKS_PER_SEC << " tiques por segundo." << std::endl;

    clock1 = clock();
    for( int indice = 1; indice <= ITERACOES; indice++)
    {
        buffer1 = (char *) malloc( indice);
        buffer1[indice-1] = indice;
        buffer2 = (char *) malloc( indice);
        buffer2[indice-1] = indice;
        free( buffer1);
        free( buffer2);
    }
    clock2 = clock();

    std::cout << "Malloc: " << double( (clock2 - clock1 )) / CLOCKS_PER_SEC << "s" << std::endl;

    clock1 = clock();
    for( int indice = 1; indice <= ITERACOES; indice++)
    {
        buffer1 = (char *) calloc( indice, 1);
        buffer1[indice-1] = indice;
        buffer2 = (char *) calloc( indice, 1);
        buffer2[indice-1] = indice;
        free( buffer1);
        free( buffer2);
    }
    clock2 = clock();

    std::cout << "Calloc: " << double( ( clock2 - clock1 )) / CLOCKS_PER_SEC << "s" << std::endl;

    buffer1 = (char *) malloc( 1);
    buffer2 = (char *) malloc( 1);
    clock1 = clock();
    for( int indice = 1; indice <= ITERACOES; indice++)
    {
        buffer1 = (char *) realloc( buffer1, indice);
        buffer1[indice-1] = indice;
        buffer2 = (char *) realloc( buffer2, indice);
        buffer2[indice-1] = indice;
    }
    free( buffer1);
    free( buffer2);
    clock2 = clock();

    std::cout << "Realloc: " << double( (clock2 - clock1 )) / CLOCKS_PER_SEC << "s" << std::endl;
}