#include<iostream>
//#include<iomanip>

using namespace std;

//naming functions
//void - verb - verb noun
//non-void - noun that describes the value returned

void sayHi()
{
	cout << "Hi\a" << endl;
}

double pi()
{
	double result = 3.14159426;
	//one return statement
	//logic goes here
	return result;
}

double square(double n)
{
	double result = n * n;

	return result;
}

//power (x,y)
//factorial (x)

void main()
{
	cout << "before\n";
	// call the function
	sayHi();
	cout << "after\n";
	double p = pi();
	cout << p << endl;
	cout << pi() * 3 << endl;
	double z;
	cin >> z;
	cout << square(z) << endl;
	cout << square(pi()) << endl;
	//parameter vs argument

}