ПОМОГИТЕ НАПИСАТЬ КОДЫ НА С++ ОЧЕНЬ СРОЧНО НУЖНО

Код:

#include
#include
void first_task(std::ifstream &cin, std::ofstream &cout) {
int n, k = 1; cin >> n >> k;
cout << n / k;</li>
}
void second_task(std::ifstream &cin, std::ofstream &cout) {
int N; cin >> N;
cout << 2 * (N / 2 + 1);</li>
}
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);</li>
}
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) << " ";</li>
}
}
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;</li>
else
cout << g;</li>
}
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;
}

ПОМОГИТЕ НАПИСАТЬ КОДЫ ** С++ ОЧЕНЬ СРОЧНО НУЖНО