#include "stdio.h"

class maths
{
private :
	void square ( int a ) const { printf ( "The square of %d is %d\n", a, a * a ) ; }
	void cube ( int a ) const { printf ( "The cube of %d is %d\n", a, a * a * a ) ; }
	void fourthpower ( int a ) const { printf ( "The fourth power of %d is %d\n", a, a * a * a * a ) ; }
	void ( maths :: * functionpointers [ 3 ] ) ( int ) const ;
	/*
	the above line declares an array called functionpointers that has three ( 3 ) elements which are all pointers ( * ) to functions in the scope of the class maths ( maths :: ) and take a single integer as parameter ( int ) and return nothing ( void ) and do not modify the contents of the class in anyway ( const )
	*/
public :
	maths ()
	{
		functionpointers [ 0 ] = & maths :: square ;
		functionpointers [ 1 ] = & maths :: cube ;
		functionpointers [ 2 ] = & maths :: fourthpower ;
	}
	void executefunction ( int functionnumber, int inputforfunction )
	{
		if ( functionnumber < 0 || functionnumber > 2 ) return ;
		( this -> * functionpointers [ functionnumber ] ) ( inputforfunction ) ;
		// this line calls the function which is pointed ( * ) to by the functionnumber-th element of the functionpointers array which is a member of the object pointed to by the current object pointer ( this ) and passes the function the value of the variable inputforfunction as a parameter
	}
} ;

int main ( void )
{
	maths mathsinstance ;
	for ( int count = 0; count < 3; count ++ )
		mathsinstance . executefunction ( count, 2 ) ;
}