What do you guys think of this? Its my first attempt at a useful C++ program. I would prefer to use if statements but I'm following a book and will learn it eventually. I might have used some time consuming code but I wanted to test my knowledge of functions.

Code:

#include <iostream>
float CircleArea(long int Radius, const float Pi);
float CircleCircumference(long int Radius, const float Pi);
/*Program created by ComDriver
13th Febuary 2005
This program can find a circle's area and circumference*/
int main()
{
long int MenuChoice, Radius, Diameter, Circumference;
const float Pi = 3.141592653589793238462633832795;
//Menu starts here
std::cout << "Menu- Find a cicle's-\n\n";
std::cout << "1. Area\n";
std::cout << "2. Circumference\n";
//Menu ends here
std::cout << "What would you like to do? ";
std::cin >> MenuChoice;
std::cin.ignore(80,'\n');
//The users Menu choice on what he wants to find is evaluated here
if (MenuChoice == 1)
{
std::cout << "\nWhat is the radius of the circle (in centimetres): ";
std::cin >> Radius;
std::cin.ignore(80,'\n');
std::cout << "\nThe circle's area is: " << CircleArea(Radius, Pi) << " square cm.";
}
if (MenuChoice == 2)
{
std::cout << "\nWhat is he radius of the circle: ";
std::cin >> Radius;
std::cin.ignore(80,'\n');
std::cout << "\nThe circumference of the circle is: " << CircleCircumference(Radius, Pi) << "cm";
}
std::cin.get();
return 0;
}
//This function finds a circles area
float CircleArea(long int Radius, const float Pi)
{
return (Pi*Radius*Pi*Radius);
}
//This function finds a circles circumference
float CircleCircumference(long int Radius, const float Pi)
{
return (2*Pi*Radius);
}