C++ Fundamentals · Final Project · Lesson 24 of 24

Building and Testing

Concept

Building and Testing

Combine variables, functions, loops, and a class from this course into one working program, then test it with different inputs.

By the end of this lesson

Explain the core idea behind Building and Testing.
Predict output before running a change.
Test one realistic and one unusual input.
Use the result to make the next decision.

How to study this page

1. Read one concept.
2. Change the example.
3. Run, compare, and explain.
4. Complete the challenge below.

ExampleRunnable

double average(int scores[], int count) {
    int total = 0;
    for (int i = 0; i < count; i++) total += scores[i];
    return static_cast<double>(total) / count;
}

Try it Yourself »

Self-check before continuing

Without looking at the example, describe what changes when you modify one input in Building and Testing. Then reopen the editor and prove your explanation with a small test.

You are ready to continue when you can predict, test, and explain the result.

Your turn

Extend the average function above to also print a pass/fail message.

Loading editor…

Console

Output will appear here...