B06 | Create reusable PHP functions
Basic level · Lesson B06
B06 | Create reusable PHP functions
Result: small library to measure progress.
Core concept: A function names a responsibility and returns a result.
Guideline time: 75–100 minutes.
What do you do when a stone appears three times?
You turn it into a function. This way you correct the rule in one place, you can test it and you better express the intention of the program.
Previous connection
In B05 we repeat a presentation. Now we will avoid repeating logic.
Concepts
A function can receive parameters, validate assumptions and return a value. Local scope prevents a function from accidentally depending on external variables.
Guided laboratory
<?php
function progressPercentage(float $completed, float $goal): float
{
if ($goal <= 0) {
return 0;
}
return min(100, ($completed / $goal) * 100);
}
echo round(progressPercentage(6, 10), 1) . "%";
The function does not print: it calculates and returns. The presentation decides how to show.
Medium Mission
Create three functions: percentage, sessions required, and progress message. Use clear names and test each one with two values.
University Extension
Define contracts using types, decide how to handle invalid input, and compare returning a neutral value to throwing an exception. At this level you implement a policy and document your limit.
Tests
Normal goal, zero goal, progress greater than goal and decimals.
Delivery
Send functions, test table and sole responsibility explanation. SEND TO TUTOR.
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