HELP - Menu won't function

[Adalaide]

I have a project for c++ and I am having a hard time getting the menu to work. I have tried so many things and I just can't get it!
I would really appreciate any help anyone can give me. Thank you!

#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;
int main()
{

double areaCir;
double radiusCir;
double areaRec;
double lengthRec;
double widthRec;
double areaTri;
double baseTri;
double heightTri;
int userChoice;
const int CIRCLE_CHOICE = 1;
const int RECTANGLE_CHOICE = 2;
const int TRIANGLE_CHOICE = 3;
const int QUIT_CHOICE = 4;

cout << "Hello, welcome to area calculations of basic geometry.";
cout << endl;
cout << "Let's start by choosing your shape.";
cout << endl;
cout << "1. Area of a circle";
cout <<endl;
cout << "2. Area of a rectangle.";
cout <<endl;
cout << "3. Area of a triangle.";
cout << endl;
cout << "4. Quit.";
cout << endl;
cin >> userChoice;
cout <<endl;

if (userChoice == CIRCLE_CHOICE);
{
cout <<"Time to calculate the area of a circle!";
cout <<endl;
cout << "Please enter the radius of your circle.";
cout << endl;
cin >> radiusCir;
areaCir = M_PI*(pow(radiusCir,2)) ;
cout << "The area of your circle is " << areaCir << ".";
cout << endl;
}

if (userChoice == RECTANGLE_CHOICE);
{
cout <<"Now let's calculate the area of a rectangle.";
cout <<endl;
cout << "Please enter the length of your rectangle.";
cout << endl;
cin >> lengthRec;
cout <<"Cool. Now enter the width of your rectangle.";
cout <<endl;
cin >> widthRec;
cout << "The area of your rectange is " << widthRec * lengthRec << ".";
cout << endl;
}

if (userChoice == TRIANGLE_CHOICE);
{
cout <<"We are going to find the area of a triangle!";
cout <<endl;
cout <<"Please enter the base of your triangle.";
cout << endl;
cin >> baseTri;
cout << endl;
cout << "Great! Now enter the height of your triangle.";
cin >> heightTri;
cout << endl;
areaTri = (0.5 * baseTri) * heightTri;
cout << "The area of your triangle is " << areaTri << ".";
cout << endl;
}



return 0;
}

[jonnin]

if statements do NOT get a ; on them.
; can be a do-nothing statement.
your code says if (whatever == choice) then do nothing.
for all the cases.

a modern compiler would warn you about this.

little stuff..
enum and enum class let you define constant integers in a nice way.
small powers (squared and cubed mostly) are generally better off written x*x than pow(x,2). It does not matter here, but pow is a good bit slower than a multiply or two.

Nice work though, you seem to be having fun with the print statements. That is how so many of us got started... hey look, I can print my name 100000000 times :) Being able to make the box say something got so many 'kids' (loosely speaking, back then that meant anyone under 30) into coding in the early days...

[seeplus]

The variables can be defined within block in which they are used. Also \n can be used within quotes instead of endl

#define _USE_MATH_DEFINES
#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;

int main() {
	int userChoice {};
	const int CIRCLE_CHOICE {1};
	const int RECTANGLE_CHOICE {2};
	const int TRIANGLE_CHOICE {3};
	const int QUIT_CHOICE {4};

	cout << "Hello, welcome to area calculations of basic geometry.\b";
	cout << "Let's start by choosing your shape.\n";
	cout << "1. Area of a circle\n";
	cout << "2. Area of a rectangle.\n";
	cout << "3. Area of a triangle.\n";
	cout << "4. Quit.\n";
	cout << "Enter option: ";

	cin >> userChoice;

	if (userChoice == CIRCLE_CHOICE) {
		double radiusCir {};

		cout << "\nTime to calculate the area of a circle!\n";
		cout << "Please enter the radius of your circle: ";
		cin >> radiusCir;

		cout << "The area of your circle is " << M_PI * radiusCir * radiusCir << ".\n";
	}

	if (userChoice == RECTANGLE_CHOICE) {
		double lengthRec {}, widthRec {};

		cout << "\nNow let's calculate the area of a rectangle.\n";
		cout << "Please enter the length of your rectangle: ";
		cin >> lengthRec;

		cout << "Cool. Now enter the width of your rectangle: ";
		cin >> widthRec;

		cout << "The area of your rectangle is " << widthRec * lengthRec << ".\n";
	}

	if (userChoice == TRIANGLE_CHOICE) {
		double baseTri {}, heightTri {};

		cout << "\nWe are going to find the area of a triangle!\n";
		cout << "Please enter the base of your triangle: ";
		cin >> baseTri;

		cout << "Great! Now enter the height of your triangle.";
		cin >> heightTri;

		cout << "The area of your triangle is " << 0.5 * baseTri * heightTri << ".\n";
	}
}