Call By Value — PHP Technical Interview Questions & Answers

Call By Value

Call By Value

  • Call By Value is a PHP topic. In plain words you use it for function add($a, $b) in a marks helper. Don’t start with a slogan — start with that picture.
  • Smallest example: function name($x) { return $x; }. Type it, run it, and say what you see. If you can do that from memory, you know Call By Value.
  • From the example next to this theory: Call By Value: scores array, print avg, then high marks.
  • Trap: no return so the caller gets null. Fix that before you talk about advanced PHP.
  • Viva: what is Call By Value? Then show function name($x) { return $x; }. Then name the trap.

Technical Interview Tip: What is Call By Value? Show this: function name($x) { return $x; }. Trap: no return so the caller gets null.

Code Examples for Call By Value

Call By Value — working example

<?php
// Call By Value
$scores = [80, 90, 70];
$avg = array_sum($scores) / count($scores);
echo "avg=" . number_format($avg, 1) . "\n";
foreach ($scores as $s) {
  if ($s >= 80) echo "high: $s\n";
}

Call By Value: scores array, print avg, then high marks. Say the output.

How to Explain Call By Value to an Interviewer

What is Call By Value?

Used for function add($a, $b) a marks helper Not just the heading

Give one small example of Call By Value.

function name($x) { return $x; } Call By Value: scores array, print avg, then high marks

What mistake do beginners make with Call By Value?

no return so the caller gets null Show the fix

Where do you use Call By Value?

a marks helper function add($a, $b)