Elseif ladder execution in PHP - Step-by-Step Execution

Concept Flow - Elseif ladder execution

Start

↓

Check if condition1

|Yes↓

Execute block1

↓

End

No↓

Check if condition2

|Yes↓

Execute block2

↓

End

No↓

Check if condition3

|Yes↓

Execute block3

↓

End

No↓

Execute else block

↓

End

The program checks each condition in order. When one condition is true, it runs that block and skips the rest. If none are true, it runs the else block.

Execution Sample

PHP

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

This code checks the score and prints the grade based on the first true condition.

Execution Table

Step	Condition Checked	Condition Result	Action Taken	Output
1	$score >= 90	75 >= 90 is False	Skip if block
2	$score >= 70	75 >= 70 is True	Execute elseif block	Grade B
3	Else block	Skipped because previous condition was True	No action
4	End	Execution complete	Program ends

💡 Condition '$score >= 70' is True, so elseif block runs and rest are skipped.

Variable Tracker

Variable	Start	After Step 1	After Step 2	Final
$score	75	75	75	75

Key Moments - 2 Insights

Why does the else block not run even though it is present?

Because the elseif condition at step 2 is True, the program executes that block and skips the else block as shown in execution_table row 3.

What happens if the first condition is True?

If the first condition is True, the program executes the first if block and skips all elseif and else blocks, similar to how step 2 works for the elseif.

Visual Quiz - 3 Questions

Look at the execution table, what is the output at step 2?

A Grade A

B Grade C

C Grade B

D No output

💡 Hint

Check the 'Output' column in execution_table row 2.

At which step does the program decide to skip the else block?

A Step 3

B Step 2

C Step 1

D Step 4

💡 Hint

Look at the 'Action Taken' column in execution_table row 3.

If $score was 95, which step would output text?

A Step 2

B Step 1

C Step 3

D Step 4

💡 Hint

Refer to the condition checks and outputs in execution_table for $score = 75 and imagine $score = 95.

Concept Snapshot

if (condition1) {
  // block1
} elseif (condition2) {
  // block2
} else {
  // else block
}

Checks conditions in order, runs first true block, skips rest.

Full Transcript

This example shows how PHP checks conditions in an elseif ladder. It starts by checking the first if condition. If false, it moves to the elseif condition. If that is true, it runs that block and skips the else block. If none are true, it runs the else block. The variable $score is 75, so the first condition is false, the second is true, and the program prints 'Grade B'. The else block is skipped because a previous condition was true.