need programming help! (C++)

#include "stdafx.h"


int _tmain(int argc, _TCHAR* argv[])
{
	return 0;
}


#include <iostream>

using namespace std;

int main()
{
	float length;
	float width;
	float height;
	float pi;
	float volume;
	float area;

	pi = 3.1416;

	cout << "The length of the shape  is: ";
	cin >> length;

	cout << "The width of the shape  is: ";
	cin >> width;

	cout << "The height of the shape  is: ";
	cin >> height;

	if (height == 0 && length > 0 && width > 0) 
	{
		cout << "The area of the rectangle is: ";
		cout << length * width;
	}

	else if (height > 0 && length > 0 && width > 0){
		cout << "The volume of the rectangular prism is: ";
		cout << length * width * height;
	}
	else if (width > 0 && height == 0 && length == 0){
		cout << "The area of the circle is: ";
		cout << (width / 2) * (width / 2) * pi;
	}
	else if (width > 0 && height > 0 && length == 0){
		cout << "The volume of the cylinder is: ";
		cout << (width / 2) * (width / 2) * pi * height;
	}


	system("pause");
}