Code Before Using Functions:

    
#include <iostream>
using namespace std;

int main() {
    double rectangleWidth = 5.0;
    double rectangleHeight = 3.0;
    double rectangleArea = rectangleWidth * rectangleHeight;  //Area is width*height

    double circleRadius = 2.5;
    double circleArea = 3.14159265359 * circleRadius * circleRadius;

    cout << "Area of the rectangle: " << rectangleArea << endl;
    cout << "Area of the circle: " << circleArea << endl;

    return 0;
}

Code Using Functions:

    
#include <iostream>
using namespace std;

double calculateRectangleArea(double width, double height) {
    return width * height; //Area is width*height
}

double calculateCircleArea(double radius) {
    return 3.14159265359 * radius * radius;  //Area is 3.14*pi*r^2
}

int main() {
    double rectangleWidth = 5.0;
    double rectangleHeight = 3.0;
    double rectangleArea = calculateRectangleArea(rectangleWidth, rectangleHeight);

    double circleRadius = 2.5;
    double circleArea = calculateCircleArea(circleRadius); //Call the function

    cout << "Area of the rectangle: " << rectangleArea << endl;
    cout << "Area of the circle: " << circleArea << endl;

    return 0;
}

By modularizing the code, you can create separate functions for calculating the area of each shape, making the code more organized and easier to maintain. In the revised code, the calculateRectangleArea and calculateCircleArea functions have been created to modularize the