/*create a program with an area function that is overloaded to calcuilate
the area of a circle (given the radius)
the area of rectangle (given length and width)
the area of triangle (given the three side of the triangle)*/
#include <iostream>
#include <cmath>
using namespace std;

#define PI 3.14159

// Area of a circle
double area(double radius) {
    return PI * radius * radius;
}

// Area of a rectangle
double area(double length, double width) {
    return length * width;
}

// Area of a triangle using Heron's formula
double area(double a, double b, double c) {
    double s = (a + b + c) / 2; // semi-perimeter
    return sqrt(s * (s - a) * (s - b) * (s - c));
}

int main() {
    int choice;

    cout << "Choose the shape to calculate the area:" << endl;
    cout << "1. Circle" << endl;
    cout << "2. Rectangle" << endl;
    cout << "3. Triangle" << endl;
    cout << "Enter your choice (1/2/3): ";
    cin >> choice;

    if (choice == 1) {
        double radius;
        cout << "Enter the radius of the circle: ";
        cin >> radius;
        cout << "The area of the circle is: " << area(radius) << endl;
    }
    else if (choice == 2) {
        double length, width;
        cout << "Enter the length and width of the rectangle: ";
        cin >> length >> width;
        cout << "The area of the rectangle is: " << area(length, width) << endl;
    }
    else if (choice == 3) {
        double a, b, c;
        cout << "Enter the lengths of the three sides of the triangle: ";
        cin >> a >> b >> c;

        // Check if a valid triangle can be formed with the given sides
        if (a + b > c && a + c > b && b + c > a) {
            cout << "The area of the triangle is: " << area(a, b, c) << endl;
        } else {
            cout << "Invalid triangle sides!" << endl;
        }
    } else {
        cout << "Invalid choice!" << endl;
    }

    return 0;
}