// Code derived from Stroustrup's PPP2 book
// § 4.5.2 Function declarations
//  -and beginning on p 117

#include <iostream>

using std::cout;

int    square(int);   // declaration of square
double sqrt(double);  // declaration of sqrt

int main()
{
  int x = square(44);

  cout << x << '\n';  // output above variable value to console...
}

// for now 'elsewhere' is simply below the definition of main() in this codefile
//  -for library software this definition will usually be in a separate codefile

int square(int x)  // definition of square
{
  return x * x;
}