7. Function definitions

• 
  #include <iostream>
  
  int square( int x )
  {
      return x * x;
  }
  
  void display( int x )
  {
      std::cout << x;
  }
  
  int main( )
  {
      int value = 5;
      int result = square( value );
      display( result );
      return 0;
  }