[C++] Square Circle Triangle

#include <iostream>
using namespace std;
void circle();
void triangle();
void square();

int main()
{
int choice;
cout << "Select the shape you would like to solve for: " << endl;
cout << "1. Circle" << endl;
cout << "2. Triangle" << endl;
cout << "3. Square" << endl;
cin >> choice;
if (choice == 1)
{
circle();
}
else if(choice == 2)
{
triangle();
}
else if(choice == 3)
{
square();
}
return 0;
}
void circle()
{
double area, circumference, radius;
const double pi = 3.14;
cout << "You have selected: Circle" << endl;
cout << "Please enter the radius of the circle: " << endl;
area = pi * radius * radius;
circumference = 2 * pi * radius;
cout << "The Area of a Circle is: " << area << endl;
cout << "The Circumference of a Circle is: " << circumference << endl;
}
void triangle()
{
double area, height, base;
cout << "You have selected: Triangle" << endl;
cout << "Please enter the height of the triangle: " << endl;
cin >> height;
cout << "Please enter the base of the triangle: " << endl;
cin >> base;
area = .5 * base * height;
cout << "The Area of the Triangle is: " << area << endl;
}
void square()
{
double side, area, perimeter;
cout << "You have selected: Square" << endl;
cout << "Please enter the side of the square: " << endl;
cin >> side;
area = side * side;
perimeter = 4 * side;
cout << "The Area of the Square is: " << area << endl;
cout << "The Preimeter of the Square is: " << perimeter << endl;
}