math++

#include <iostream>
#include <iomanip> 
#define _USE_MATH_DEFINES
#include<cmath>
using namespace std;

long double pi = 3.141592653589793;

int main() {
    double x, y, z, w;
    cout << std::setprecision(16) << M_PI << endl << pi << endl << sin(M_PI/2) << endl;
    cout << hypot(3,4) << endl << pow(4,0.5) << endl;
}