If-else execution flow in PHP - Step-by-Step Execution

Concept Flow - If-else execution flow

Start

↓

Evaluate condition

↓

Execute if-block

↓

End

↓

Execute else-block

↓

End

The program checks a condition. If true, it runs the if-block. Otherwise, it runs the else-block. Then it ends.

Execution Sample

PHP

<?php
$age = 18;
if ($age >= 18) {
    echo "Adult";
} else {
    echo "Minor";
}
?>

This code checks if age is 18 or more, prints 'Adult' if true, else prints 'Minor'.

Execution Table

Step	Condition ($age >= 18)	Result	Branch Taken	Output
1	18 >= 18	True	if-block	Adult
2	End of if-else	-	-	-

💡 Condition is true, so if-block runs and program ends after printing 'Adult'.

Variable Tracker

Variable	Start	After Step 1	Final
$age	18	18	18

Key Moments - 2 Insights

Why does the program print 'Adult' and not 'Minor'?

Because at Step 1 in the execution_table, the condition ($age >= 18) is true, so the if-block runs and prints 'Adult'. The else-block is skipped.

What happens if the condition is false?

If the condition was false, the else-block would run instead, printing 'Minor'. This is shown by the 'Branch Taken' column in the execution_table.

Visual Quiz - 3 Questions

Look at the execution_table, what is the output at Step 1?

A Minor

B 18

C Adult

D No output

💡 Hint

Check the 'Output' column at Step 1 in the execution_table.

At which step does the program decide which block to run?

A Step 2

B Step 1

C Before Step 1

D After Step 2

💡 Hint

Look at the 'Condition' and 'Branch Taken' columns in the execution_table.

If $age was 16, how would the 'Branch Taken' change in the execution_table?

A It would change to 'else-block'

B It would still be 'if-block'

C No branch would be taken

D Both blocks would run

💡 Hint

Refer to the 'Condition' and 'Branch Taken' logic in the execution_table.

Concept Snapshot

if (condition) {
  // code if true
} else {
  // code if false
}

Checks condition once.
Runs if-block if true.
Runs else-block if false.

Full Transcript

This PHP code uses an if-else statement to check if the variable $age is 18 or more. If true, it prints 'Adult'. Otherwise, it prints 'Minor'. The execution flow starts by evaluating the condition $age >= 18. Since $age is 18, the condition is true, so the if-block runs and outputs 'Adult'. The else-block is skipped. Variables remain unchanged during this process. This flow helps decide between two paths based on a condition.