How To Think Like A Computer ITSC 1212 - Functions First Edition

Once we have written the program, we need to verify that the program works. There are many, many different ways to accomplish this task, but for the purposes of this textbook it will be easiest to run the program with different values and verify that the result is correct each time. If at any point the result is not correct, then we know there is something wrong within the program.

Let’s look at an example program and test it to ensure it’s working properly. NOTE: In the following programs the initial numbers will be defined as str type instead of int for the sake of demonstration.

As you can see, 1 and 1 resulted in 2. However, it’s not good practice to only check it with one combination of values. Let’s run it a few more times with other values to ensure it works properly.

We got 8, looks like it works perfectly. Let’s try it one more time with another set of values.

Good thing we checked with a decimal! With this set of numbers, a ValueError occured because the program is trying to convert the string to integer, but can’t due to the decimal. To address this issue, the conversion can be changed from integer to float.

Looks like our program even works with decimal numbers now. Remember to double check your program with multiple sets of input to ensure it works properly. If we had stopped after checking that 1 + 1 worked we would not have noticed that the program didn’t work with decimals here.