If-else execution flow in PHP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of nested if-else statements

What is the output of the following PHP code?

PHP

<?php
$value = 10;
if ($value > 5) {
    if ($value < 15) {
        echo "Inside range";
    } else {
        echo "Too high";
    }
} else {
    echo "Too low";
}
?>

A Too low

B Inside range

C Too high

D No output

💡 Hint

Check the conditions step by step starting from the outer if.

The variable $value is 10, which is greater than 5 and less than 15, so the inner if condition is true and it prints 'Inside range'.

❓ Predict Output

intermediate

If-else with multiple conditions

What will this PHP code output?

PHP

<?php
$score = 75;
if ($score >= 90) {
    echo "Grade A";
} elseif ($score >= 80) {
    echo "Grade B";
} elseif ($score >= 70) {
    echo "Grade C";
} else {
    echo "Grade F";
}
?>

A Grade C

B Grade B

C Grade A

D Grade F

💡 Hint

Check which condition matches the score starting from the top.

The score is 75, which is not >= 90 or >= 80, but is >= 70, so it prints 'Grade C'.

🔧 Debug

advanced

Identify the error in if-else syntax

What error does this PHP code produce when run?

PHP

<?php
$number = 5;
if ($number > 0)
    echo "Positive";
else
    echo "Non-positive";
else
    echo "Zero";
?>

A No output

B Outputs 'Positive'

C Outputs 'Non-positive'

D SyntaxError: Unexpected 'else' after else

💡 Hint

Check the structure of if-else statements and how many else blocks are allowed.

The code has two else blocks for one if, which is invalid syntax in PHP and causes a syntax error.

🧠 Conceptual

advanced

Understanding if-else execution flow

Consider this PHP code snippet:

$x = 3;
if ($x > 0) {
    echo "A";
} elseif ($x > 2) {
    echo "B";
} else {
    echo "C";
}

What will be the output?

A A

B B

C C

D No output

💡 Hint

Remember that elseif is only checked if the previous if condition is false.

Since $x is 3, the first if condition ($x > 0) is true, so it prints 'A' and skips the elseif and else blocks.

❓ Predict Output

expert

Output with complex if-else and logical operators

What is the output of this PHP code?

PHP

<?php
$a = 4;
$b = 7;
if ($a > 3 && $b < 10) {
    if ($a + $b > 10) {
        echo "X";
    } else {
        echo "Y";
    }
} else {
    echo "Z";
}
?>

A No output

B Z

C X

D Y

💡 Hint

Evaluate the conditions carefully, including the logical AND and sums.

Both conditions in the outer if are true ($a=4 >3 and $b=7 <10). The inner if checks if 4+7>10, which is true, so it prints 'X'.