Speed compare between wcscpy, lstrcpyW, while loop and memcpy

strcpy.cpp

#include <iostream>
#include <cstring>
#include <functional>
#include <chrono>
#include <windows.h>

#define N 1024


uint64_t TestTime(std::function<void()> f)
{
    auto t = std::chrono::high_resolution_clock::now();
    for (int i = 0; i < 1000000; ++i)
    {
        f();
    }
    return std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::high_resolution_clock::now() - t).count();
}


int main(int argc, char const *argv[])
{
    wchar_t a[N], b[N], c[N], d[N], e[N], f[N];

    for (int i = 0; i < N-1; ++i)
    {
        a[i] = rand() % 65535;
    }
    a[N-1] = 0;

    std::cout << TestTime([&] () {wcscpy(b, a);}) << std::endl;
    std::cout << TestTime([&] () {lstrcpyW(c, a);}) << std::endl;
    std::cout << TestTime([&] () {int i = 0; while (d[i] = a[i]) i++;}) << std::endl;
    std::cout << TestTime([&] () {memcpy(e, a, (wcslen(a) + 1) * sizeof(wchar_t));}) << std::endl;
    std::cout << TestTime([&] () {memcpy(f, a, N * sizeof(wchar_t));}) << std::endl;    // cheat

    if (wcscmp(b, a) || wcscmp(c, a) || wcscmp(d, a) || wcscmp(e, a) || wcscmp(f, a))
    {
        std::cout << "Something went wrong." << std::endl;
    }

    return 0;
}