Write a C++ program to demonstrate the working of a calculator.

#include<iostream.h>
    float add(float,float);
    float subtract(float,float);
    float multiply(float,float);
    float divide(float,float);
    void main()
{
	float num_1,num_2;
	
	char select,choice;
	cout << "                      *-:CALCULATOR PROGRAM:-* " << endl;
     
	cout << "                      -**********************-"<< endl ;
	
	cout << endl;
	cout << "                          -:RESTRICTIONS:- \n "<< endl;

	cout << "#1) PLEASE ENTER INTEGER TAYPE VALE LIKE (.......-2,-1,0,1,2,.....):" << endl; 
    
	cout << endl;
	cout << "#2) PLEASE ENTER VALID OPERATOR LIKE (*,-,/,+):" << endl;
	
	cout << "--------------------------------------------------------------" << endl;
input: cout << endl;
	cout << "       ENTER FIRST DIGIT  : " ;
	cin >> num_1;
	cout << endl;
	
	cout << "SELECT ONE OPERATION IN WHICH OF THESE (+,*,-,/) THAT YOU WANT TO OPERATE:\n\n";

	cout << "YOUR SELECTED OPERATION IS: ";
	
	cin >> select;
	cout << endl;
    cout << "       ENTER SECOND DIGIT : ";
	cin >> num_2;
	cout << endl;

	if ( num_1 > 3.4e-38 && num_1 < 3.4e38 && num_2 > 3.4e-38 && num_2 < 3.4e3 && select == '+' || select == '*' || select == '-' || select == '/' )
	{

	if ( select == '+' )
		
		cout << "            YOUR ANSWER IS: " << add(num_1,num_2);
	if( select== '-' )
		
		cout << "            YOUR ANSWER IS: " << subtract(num_1,num_2);
	if ( select == '*' )
		
		cout << "            YOUR ANSWER IS: " <<multiply(num_1,num_2) ;
	if ( select == '/' )
		
		cout << "            YOUR ANSWER IS: " << divide(num_1,num_2);
	cout << endl;
	cout << "-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-"<<endl;
	
	cout << endl;
    cout << "ENTER 'y' TO CONTINUE AND 'n' TO STOP :\n" << endl;
	cout << "                 DO YOU WANT YO CONTNUE [y/n]:  ";
	cin >> choice;
	if ( ( choice == 'y' ) || ( choice == 'y' ) )
	goto input;
	}
	else
		cout << endl ;
		cout << "               INVALID INPUT!" << endl;
		cout << endl;
	
	
	
	
	
}
float add ( float x, float y)
{
	return ( x + y );
}
float subtract ( float x, float y)
{
	return ( x - y );
}
float multiply ( float x, float y)
{
	return ( x * y );
}
float divide ( float x, float y)
{
	return ( x / y );
}