Reusability and maintenance - Mini Project: Build & Apply

Reusability and maintenance

📖 Scenario: You are working on a small program that calculates the area of different shapes. To keep your code clean and easy to maintain, you want to reuse the area calculation logic by putting it inside functions.

🎯 Goal: Create reusable functions to calculate the area of a rectangle and a circle, then use these functions to print the areas for given dimensions.

📋 What You'll Learn

Create a function called rectangle_area that takes two double parameters length and width and returns their product as double.

Create a function called circle_area that takes one double parameter radius and returns the area of the circle using the formula 3.14159 * radius * radius.

In main, declare variables rect_length and rect_width with values 5.0 and 3.0 respectively.

In main, declare a variable circle_radius with value 2.0.

Call the functions rectangle_area and circle_area with the declared variables and print the results with descriptive text.

💡 Why This Matters

🌍 Real World

Reusable functions are used in real software to avoid repeating code and to make programs easier to update and fix.

💼 Career

Understanding how to write and use functions is essential for any programming job, as it improves code quality and teamwork.

1

Create variables for rectangle and circle dimensions

In the main function, create double variables called rect_length and rect_width and set them to 5.0 and 3.0 respectively. Also create a double variable called circle_radius and set it to 2.0.

C

#include 

int main() {
    // Create double variables rect_length, rect_width, and circle_radius with values 5.0, 3.0, and 2.0
    // Your code here
    return 0;
}

Need a hint?

Use the syntax double variable_name = value; to create each variable.

2

Create function to calculate rectangle area

Above the main function, create a function called rectangle_area that takes two double parameters named length and width. The function should return a double which is the product of length and width.

C

#include 

// Create function rectangle_area with parameters length and width
// Your code here

int main() {
    double rect_length = 5.0;
    double rect_width = 3.0;
    double circle_radius = 2.0;
    return 0;
}

Need a hint?

Define the function with double return type and multiply the two parameters.

3

Create function to calculate circle area

Above the main function, create a function called circle_area that takes one double parameter named radius. The function should return a double which is the area calculated as 3.14159 * radius * radius.

C

#include 

double rectangle_area(double length, double width) {
    return length * width;
}

// Create function circle_area with parameter radius
// Your code here

int main() {
    double rect_length = 5.0;
    double rect_width = 3.0;
    double circle_radius = 2.0;
    return 0;
}

Need a hint?

Use the formula for circle area and return the result.

4

Call functions and print the areas

In the main function, call rectangle_area with rect_length and rect_width and store the result in a double variable called rect_area. Call circle_area with circle_radius and store the result in a double variable called circ_area. Then print both areas using printf with the exact text:
"Rectangle area: %f\n" and "Circle area: %f\n".

C

#include 

double rectangle_area(double length, double width) {
    return length * width;
}

double circle_area(double radius) {
    return 3.14159 * radius * radius;
}

int main() {
    double rect_length = 5.0;
    double rect_width = 3.0;
    double circle_radius = 2.0;
    // Call rectangle_area and circle_area, store results in rect_area and circ_area
    // Print the areas with printf
    // Your code here
    return 0;
}

Need a hint?

Use printf("Rectangle area: %f\n", rect_area); and similarly for circle area.