Why operators matter in PHP - Challenge Your Understanding

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of mixed operator precedence

What is the output of this PHP code snippet?

PHP

<?php
$result = 2 + 3 * 4 - 5 / 5;
echo $result;
?>

A 15

B 14

C 13

D 12

💡 Hint

Remember multiplication and division happen before addition and subtraction.

Multiplication and division are done first: 3*4=12 and 5/5=1. Then addition and subtraction: 2+12=14, 14-1=13.

❓ Predict Output

intermediate

Output of string concatenation and addition

What will this PHP code output?

PHP

<?php
$a = '5';
$b = 3;
$c = $a + $b;
$d = $a . $b;
echo "$c,$d";
?>

A 8,8

B 53,8

C 53,53

D 8,53

💡 Hint

The plus operator converts strings to numbers, dot operator concatenates strings.

Adding '5' + 3 converts '5' to 5, so 5+3=8. Concatenating '5' . 3 results in '53'.

❓ Predict Output

advanced

Output of combined logical and bitwise operators

What is the output of this PHP code?

PHP

<?php
$x = 6; // binary 110
$y = 3; // binary 011
if (($x & $y) && ($x | $y)) {
    echo 'Yes';
} else {
    echo 'No';
}
?>

A Yes

B No

C Syntax Error

D 0

💡 Hint

Bitwise AND and OR produce non-zero values, which are true in logical context.

($x & $y) = 2 (true), ($x | $y) = 7 (true), so condition is true and 'Yes' is printed.

❓ Predict Output

advanced

Output of increment operators in expressions

What does this PHP code output?

PHP

<?php
$a = 5;
$b = $a++ + ++$a;
echo $b;
?>

A 12

B 13

C 10

D 11

💡 Hint

Post-increment returns the value before increment, pre-increment increments first.

Initially $a=5. $a++ returns 5 then $a=6. ++$a increments $a to 7 then returns 7. So 5+7=12.

❓ Predict Output

expert

Output of complex operator chaining with assignment

What is the output of this PHP code?

PHP

<?php
$x = 4;
$y = 2;
$x += $y *= $x + 1;
echo "$x,$y";
?>

A 8,14

B 14,10

C 14,8

D 10,14

💡 Hint

Assignment operators evaluate right to left, watch the order carefully.

First $x + 1 = 5. Then $y *= 5 → $y = 2*5 = 10. Then $x += $y → $x = 4 + 10 = 14. Output: 14,10