Perimeter of a Rectange

Backgroud

One of the first geometry problems you learn is how to calculate the perimeter of a rectangle. After this, by taking small steps, you learn more advanced maths. It is the same with programming: first you takesmall steps, then you build up higher. Let's go back and implement a programm that calculates a rectangle's perimeter.

In a file called rectangle.py, implement a program in Python that prompts the user for the length of a rectangle, then prompts for the height of the rectangle. Your program should then sends those inputs to a function called calc_perimeter that returns the length of the perimeter of that rectangle. Finally, print the returned value and tell the user how long the perimeter of their rectangle is.

Understanding

A rectangle is any shape with four straight sides that has right angles (90 degrees angles) in each corner. A rectangle is any shape like the following:

1
2
3

flowchart TD
    A[Rectangle]
    B{Rectangle}

If laid on its side, a rectangle has two vertical sides who are lengths equal to each other, and two horizontal sides whose lengths may be different from the vertical, but are equal to each other. A rectangle is said to have a height (the length of a vertical side) and a width (the length of a horizontal side). As you may have guessed, a square is a subtype of rectangle where the height and width are the same.

Your programm will need to take in two inputs, which would be the two sides of the perimeter (side a and side b). Then with the help of calc_perimeter function you are going to calculate the perimeter, and print it.

Before You Begin

Execute cd by itself in your terminal window. You should find that your terminal window’s prompt resembles the below:

Next execute

1	`mkdir rectangle`

to make a folder called rectangle in your codespace.

Then execute

1	`cd rectangle`

to change directories into that folder.

You should now see your terminal prompt as rectangle/ . You can now execute

1	`code rectangle.py`


to make a file called

rectangle.py` where you’ll write your program.

Specification

You will implement two functions: main and calc_perimeter.

In the main function you will prompt the user for two numbers (the height and the width), then call the calc_perimeter function, passing in the values for the height and the width as argument.

In the calc_perimeter function you will take in two inputs as the function parameters which would be the two sides of a rectangle. Then you will calculate the perimeter, and return the number.

Hints

Don't forget that input returns a string, and you need an int: https://docs.python.org/3/library/functions.html#int

More about functions: https://docs.python.org/3/tutorial/controlflow.html#defining-functions

How to Test

Run your program with python rectangle.py. Type 5 and press Enter. At the next prompt, type 3 and press Enter. Your program should output 14.
Run your program with python rectangle.py. Type 10 and press Enter. At the next prompt, type 5 and press Enter. Your program should output 30.
Run your program with python rectangle.py. Type 2 and press Enter. At the next prompt, type 4 and press Enter. Your program should output 12.

If you run into an error saying your file cannot be opened, retrace your steps to be sure that you are inside your rectangle folder and have saved your rectangle.py file there.

You can execute the below to check your code using check50, a program that CS50 will use to test your code:

1	`check50 alum-challenges/problems/main/python/week-0/rectangle/tests`

* Green smiles mean your program has passed a test! * Red frowns will indicate your program output something unexpected. * Orange neutral faces mean you must fix the failed check before those checks can run.

Visit the URL that check50 outputs to see the input check50 handed to your program, what output it expected, and what output your program actually gave.

How to Submit

Coming soon