#include <iostream>
using namespace std;

int squareByValue(int x);
void squareByRef(int & x);
void squareByPointer(int *pt);

int main()
{

  int number{3};

  cout << squareByValue(number) << endl;

  cout << number << endl;
  squareByRef(number);

  cout << number << endl;

  squareByPointer(&number);

  cout << number << endl;



}

int squareByValue(int x)
{
  return x*x;
}

void squareByRef(int & x)
{
  x*=x;
}

void squareByPointer(int *pt)
{
  *pt *= *pt;
}