AI Computer Science Academy · Faisalabad

C++ Foundations

Test a function

Task 29 of 56 C++ Section 3 · Functions
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Test a function

Call the function with known values and compare the answer.

What you are building

The task in front of you: How do you test a fee function?.

The editor already holds a working starting point. Do not delete it and start again — read it, change one thing, run it, and watch which check moves. That loop is the whole method.

Why this matters

You are inside the section “Section 3 · Functions” of the C++ Foundations track. Everything in this section builds towards the section project, and this task is one of the pieces that project leans on.

In real work nobody marks your code — it either runs or it does not, and someone is waiting for the result. The checks here are deliberately strict about output, because a program that prints the right thing in the wrong shape fails in the real world too.

The key idea

C++ makes you say what type every value has, and the compiler believes you. That strictness is the point: the error you get at compile time is a bug you did not have to debug at runtime.

Every statement ends in a semicolon, and main() is where the program starts. Read compiler errors from the top: the first one is usually the real one.

Two mistakes to avoid

  • Forgetting std:: or the namespace, then blaming the compiler. If it says "not declared", check the include and the namespace first.
  • Declaring a variable inside an if block and using it after the block ends. The name only exists between the braces that created it.

What the automatic checks look for

The right-hand column runs 1 check every time you press Run code. Nothing is hidden:

  • The output has to contain “out:test passed”.

Task

How do you test a fee function?

The editor already contains a starting point. Change it until every check passes — the Next task button unlocks when it does.

What you start with 
#include <iostream>
using namespace std;

int fee_for(int months, int monthly) {
    return months * monthly;
}

int main() {
    if (fee_for(3, 9000) == 27000) {
        cout << "test passed" << endl;
    } else {
        cout << "test failed" << endl;
    }
    return 0;
}
C++ 1 automatic check Section 3 · Functions
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Your result

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Write your code in the middle column and press Run code.

Checks on this task:

  • Check 1

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