W3School TIY Editor

#include <iostream> #include <cmath> using namespace std; int main() { const double PI = 3.141592653589793; cout << cos(3) << "\n"; cout << cos(-3) << "\n"; cout << cos(0) << "\n"; cout << cos(PI) << "\n"; cout << cos(PI / 2.0) << "\n"; return 0; }