Question

How do I write a Python program that calculates the area and perimeter of a rectangle given its length and width?

Answer 1

To write a Python program that calculates the area and perimeter of a rectangle based on user-supplied length and width, you can follow the steps below. An example is provided for clarity.

Here’s how the program could look:

```python
def calculate_area(length, width):
return length * width

def calculate_perimeter(length, width):
return 2 * (length + width)

def main():
# Get the length and width from the user
length = float(input("Enter the length of the rectangle: "))
width = float(input("Enter the width of the rectangle: "))

# Calculate area and perimeter
area = calculate_area(length, width)
perimeter = calculate_perimeter(length, width)

# Output the results
print(f"The area of the rectangle is: {area}")
print(f"The perimeter of the rectangle is: {perimeter}")

# Run the main function
if __name__ == "__main__":
main()
```

### Explanation:

1. **Functions**:
- `calculate_area(length, width)`: This function takes the length and width of the rectangle and returns the area (length * width).
- `calculate_perimeter(length, width)`: This function calculates and returns the perimeter (2 * (length + width)).

2. **Main Function**:
- It prompts the user for the length and width of the rectangle, converts the input to a float, and stores it in the `length` and `width` variables.
- It calls the area and perimeter functions and stores the results in variables `area` and `perimeter`.
- Finally, it prints the calculated area and perimeter.

3. **Entry Point**:
- The `if __name__ == "__main__":` block ensures that the `main()` function runs when the script is executed directly.

### How to Run:
- Save the program in a `.py` file, for example, `rectangle_calculator.py`.
- Open the terminal or command prompt.
- Run the program by typing `python rectangle_calculator.py` (you may need to use `python3` depending on your setup).
- Input the length and width when prompted, and the program will output the area and perimeter of the rectangle.