НАПИСАТЬ КОДЫ НА С++ ОЧЕНЬ НУЖНО

Код:

#include <fstream>#include <cmath>void first_task(std::ifstream &cin, std::ofstream &cout) {    int n, k = 1; cin >> n >> k;    cout << n / k;}void second_task(std::ifstream &cin, std::ofstream &cout) {    int N; cin >> N;    cout << 2 * (N / 2 + 1);}void third_task(std::ifstream &cin, std::ofstream &cout) {    int N; cin >> N;    auto t = [](int c, int N){return c / (int) pow(10, N) % 10;};    cout << t(N, 2) + t(N, 1) + t(N, 0);}void fourth_task(std::ifstream &cin, std::ofstream &cout) {    int N; cin >> N;    for (int it = 0; it < log2(N); ++it) {        cout << pow(2, it) << " ";    }}void fifth_task(std::ifstream &cin, std::ofstream &cout) {    int h, a, b;    cin >> h >> a >> b;    int h0 = h - a, dx = a - b;    int g = 1 + h0/dx + (h0%dx + dx - 1)/dx;    if (g < 0)        cout << INFINITY;    else        cout << g;}int main() {    std::ifstream cin("input.txt");    std::ofstream cout("output.txt");    // Choose your function    int N = 0; // 0-4    void (*tasks[5]) (std::ifstream &, std::ofstream &) = {first_task, second_task, third_task, fourth_task, fifth_task};    tasks[N](cin, cout);    return 0;}