W3School TIY Editor

#include <iostream> #include <cmath> using namespace std; int main() { cout << acos(0.64) << "\n"; cout << acos(-0.4) << "\n"; cout << acos(0) << "\n"; cout << acos(1) << "\n"; cout << acos(-1) << "\n"; cout << acos(2) << "\n"; return 0; }