Delete array element benchmarking

main.c

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define N (1000 * 1000)

void array_print(int *xs, int n)
{
    for (int i = 0; i < n; ++i) {
        printf("%d ", xs[i]);
    }
    printf("\n");
}

void array_init(int *xs, int n)
{
    for (int i = 0; i < N; ++i) {
        xs[i] = i;
    }
}

void array_remove_naive(int *xs, int n, int i)
{
    assert(i < n);

    for (int j = i; j < n - 1; ++j) {
        xs[j] = xs[j + 1];
    }
}

void array_remove_memmove(int *xs, int n, int i)
{
    assert(i < n);
    memmove(xs + i, xs + i + 1, sizeof(int) * (n - i - 1));
}

void array_remove_memcpy(int *xs, int n, int i)
{
    assert(i < n);
    memcpy(xs + i, xs + i + 1, sizeof(int) * (n - i - 1));
}

int array_verify(int *xs, int n, int i)
{
    assert(i < n);

    for (int j = 0; j < i; ++j) {
        if (xs[j] != j) {
            return 0;
        }
    }

    for (int j = i; j < n; ++j) {
        if (xs[j] != j + 1) {
            return 0;
        }
    }

    return 1;
}

int main(int argc, char *argv[])
{
    int *xs = malloc(sizeof(int) * N);

    clock_t result = 0;

    for (int i = 0; i < 1000; ++i) {
        array_init(xs, N);

        clock_t start = clock();
        array_remove_memcpy(xs, N, i % N);
        clock_t end = clock();
        result += end - start;

        if (!array_verify(xs, N - 1, i % N)) {
            printf("Array is not correct\n");
            // array_print(xs, N - 1);
            return -1;
        }
    }

    printf("%f\n", (double) result / CLOCKS_PER_SEC);

    return 0;
}

results.org

memmove	naive	memcpy
1.127516	2.276486	1.761408
1.682012	2.341650	1.603680
1.693679	2.220025	1.688858