To su dat ma

https://www.youtube.com/watch?v=se3pSr_4O0U
https://www.youtube.com/watch?v=55IvG1zbzzU&fbclid=IwAR0IJwdlpIwRw6gOzQXouAp_t2PKh5zFMiQHYoUu0sQ0FtR-aP7WcD6vk44

http://mathworld.wolfram.com/PolygonArea.html

http://mathworld.wolfram.com/PolygonArea.html

https://thuvienhoasen.org/p75a7806/3/vi-mot-vai-de-nghi-de-cai-tien

https://thuvienhoasen.org/p75a7806/3/vi-mot-vai-de-nghi-de-cai-tien
https://thuvienhoasen.org/p75a24911/3/tom-tat-phat-giao

Ho den

https://thuvienhoasen.org/a4339/chuong-6-ho-den

Dem thoi gian trong C++

cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";

Đọc và xuất file trong C++

#include <iostream>
#include <stdio.h>

using namespace std;

int main()
{
    freopen("INPUT.TXT", "r", stdin);
    freopen("OUTPUT.TXT", "w", stdout);
    int x;
    cin >> x;
    cout << x;
    return 0;
}