Hello all, I recently began to learn C++ from reading a book. I'm up to chapter 4 of 24 and thought I'd like to try out what I've learnt to far. My program works fine, however I'd like some advice on the way I have written the program and whether or not it can be simplified and how. The program overall is to work of the area of some shapes. The user needs to input the shape he is using the the information required to work out the area.

Code:
```#include <iostream>

int AreaTrianlge(short int Height, short int Base)
{
std::cout << std::endl << "Working out the Area of the Triangle!" << std::endl << "The Answer is: ";
return((Height*Base)/2);
}

int AreaSquare(short int Height, short int Width)
{
std::cout << std::endl << "Working out the Area of the Sqaure!" << std::endl << "The Answer is: ";
return(Height*Width);
}

{
float PI = 3.14159;

std::cout << std::endl << "Working out the Area of the Circle!" << std::endl << "The Answer is: ";
}

int AreaTrapezium(short int Height, short int TopParallel, short int BottomParallel)
{
std::cout << std::endl << "Working out the Area of the Trapezium!" << std::endl << "The Answer is: ";
return((Height*(TopParallel+BottomParallel))/2);
}

int main()
{
short int ChoosenShape;
short int Height, Base, Width, TopParallel, BottomParallel; //Variables for Area

std::cout << "Please choose a shape:" << std::endl << "1.Triangle, 2.Square, 3.Circle or 4.Trapezium" << std::endl << "Do this by typing the number of the shape" << std::endl;
std::cin >> ChoosenShape;

if (ChoosenShape == 1)//If Triangle is choosen
{
std::cout << std::endl << "You have choosen 'Triangle'" << std::endl;
std::cout << "Please enter in the height of the Triangle:\t";
std::cin >> Height;
std::cout << "Please enter in the base of the Traingle:\t";
std::cin >> Base;
std::cout << AreaTrianlge(Height, Base) << std::endl;
}
else if (ChoosenShape == 2)//If Square is choosen
{
std::cout << std::endl << "You have choosen 'Square'" << std::endl;
std::cout << "Please enter in the height of the Square:\t";
std::cin >> Height;
std::cout << "Please enter in the base of the Square:\t\t";
std::cin >> Width;
std::cout << AreaSquare(Height, Width) << std::endl;
}
else if (ChoosenShape == 3)//If Circle is choosen
{
std::cout << std::endl << "You have choosen 'Circle'" << std::endl;
}
else if (ChoosenShape == 4)//If Trapezium is choosen
{
std::cout << std::endl << "You have choosen 'Trapezium'" << std::endl;
std::cout << "Please enter in the height of the Trapezium:\t\t\t\t";
std::cin >> Height;
std::cout << "Please enter in the Length of the Top Parallel of the Trapezium:\t";
std::cin >> TopParallel;
std::cout << "Please enter in the Length of the Bottom Parallel of the Trapezium:\t";
std::cin >> BottomParallel;
std::cout << AreaTrapezium(Height, TopParallel, BottomParallel) << std::endl;
}
else

std::cout << std::endl << "Please enter a valid shape number!" << std::endl;
return 0;
}```
Like I said before and advice on how I written the could would be amazing thanks all! P.S If this isn't the sort of post that is allowed here, then please close the thread.