Break statement with levels in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the break statement do in PHP loops?

The break statement immediately stops the execution of the current loop and exits it.

intermediate

How does break with levels work in PHP?

You can specify a number after break to exit multiple nested loops at once. For example, break 2; exits two levels of loops.

beginner

What happens if you use break 1; in a nested loop?

Using break 1; exits only the innermost loop, which is the default behavior of break without a number.

intermediate

Can you use break with levels in switch statements in PHP?

Yes, break with levels works in both loops and switch statements. It exits the specified number of enclosing loop or switch structures.

intermediate

Example: What does this code output?

for ($i = 1; $i <= 3; $i++) {
  for ($j = 1; $j <= 3; $j++) {
    if ($j == 2) {
      break 2;
    }
    echo "$i$j ";
  }
}

The output is 11 . When $j equals 2, break 2; exits both loops immediately, so only 11 is printed.

What does break 3; do inside three nested loops?

A Causes an error

B Exits only the innermost loop

C Exits all three loops immediately

D Exits the outermost loop only

break 3; exits three levels of loops, so it stops all three nested loops immediately.

What is the default level of break if no number is specified?

A 1

B 0

C 2

D It depends on the loop

By default, break exits only the innermost loop, which is level 1.

Can break 2; be used inside a single loop?

A Yes, it exits the loop twice

B No, it causes a warning or error

C Yes, it exits the loop once

D No, it does nothing

If you use break with a level greater than the number of nested loops, PHP will issue a warning.

Which statement is true about break in PHP?

A <code>break</code> can exit multiple nested loops with a number

B <code>break</code> can only exit one loop at a time

C <code>break</code> restarts the loop

D <code>break</code> only works in <code>switch</code> statements

break can exit multiple nested loops by specifying a number after it.

What will happen if you use break 0; in a loop?

A It does nothing

B It exits the loop immediately

C It behaves like <code>break 1;</code>

D It causes a fatal error

Using break 0; is invalid and causes a fatal error in PHP.

Explain how the break statement with levels works in PHP nested loops.

Think about how many loops you want to stop at once.

Describe a real-life situation where breaking out of multiple loops at once might be useful.

Imagine looking for something in a big table and stopping when found.

Practice

1.

What does the break statement do in PHP loops?

easy

A. It skips the current iteration and continues the loop.

B. It pauses the loop until a condition is met.

C. It restarts the loop from the beginning.

D. It stops the current loop immediately.

Solution

1. Step 1: Understand the purpose of break

   The break statement is used to exit a loop early when a condition is met.

2. Step 2: Compare options

   The description "It stops the current loop immediately." correctly describes break. "It skips the current iteration..." describes continue. Restarting or pausing are incorrect.

3. Final Answer:

   It stops the current loop immediately. -> Option D

4. Quick Check:

   break stops loop [OK]

Hint: Break stops loops immediately, no more iterations [OK]

Common Mistakes:

• Confusing break with continue
• Thinking break pauses instead of stops
• Assuming break restarts the loop

2.

Which of the following is the correct syntax to break out of 2 nested loops in PHP?

for (...) {
    for (...) {
        // break here
    }
}

easy

A. break;

B. break(2);

C. break 2;

D. break 1;

Solution

1. Step 1: Recall break syntax with levels

   To exit multiple nested loops, PHP uses break n; where n is the number of loops to break out of.

2. Step 2: Identify correct syntax

   break 2; correctly breaks out of 2 loops. break(2); is invalid syntax. A plain break; or break 1; breaks only one loop.

3. Final Answer:

   break 2; -> Option C

4. Quick Check:

   break 2; exits 2 loops [OK]

Hint: Use break n; to exit n nested loops in PHP [OK]

Common Mistakes:

• Using break(2) which is invalid syntax
• Forgetting to specify number for multiple loops
• Using break 1; when 2 loops need exit

3.

What is the output of this PHP code?

$count = 0;
for ($i = 0; $i < 3; $i++) {
    for ($j = 0; $j < 3; $j++) {
        $count++;
        if ($i + $j == 2) {
            break 2;
        }
    }
}
echo $count;

medium

A. 5

B. 3

C. 4

D. 6

Solution

1. Step 1: Trace nested loops and break condition

   Loops run with i and j from 0 to 2. The break triggers when i + j == 2, breaking out of both loops immediately. count++ occurs before the check.

2. Step 2: Simulate iterations

   - i=0,j=0: count=1 (sum=0 !=2)
   - i=0,j=1: count=2 (sum=1 !=2)
   - i=0,j=2: count=3 (sum=2 ==2), break 2; loops stop
   Total count = 3.

3. Final Answer:

   3 -> Option B

4. Quick Check:

   3 increments before break 2 exits both loops [OK]

Hint: Count increments before break; break n exits n loops [OK]

Common Mistakes:

• Counting increments after break condition
• Ignoring break level effect
• Assuming break only exits inner loop

4.

Find the error in this PHP code snippet:

for ($i = 0; $i < 3; $i++) {
    for ($j = 0; $j < 3; $j++) {
        if ($i == $j) {
            break 3;
        }
        echo "$i,$j\n";
    }
}

medium

A. break 3; is invalid because only 2 loops exist.

B. break 3; should be break 2; to exit both loops.

C. break 3; causes infinite loop.

D. No error, code runs fine.

Solution

1. Step 1: Count nested loops

   There are 2 nested loops: outer and inner.

2. Step 2: Check break level usage

   Using break 3; tries to break out of 3 loops, but only 2 exist, causing a fatal error.

3. Final Answer:

   break 3; is invalid because only 2 loops exist. -> Option A

4. Quick Check:

   break n must be ≤ nested loops count [OK]

Hint: Break level cannot exceed nested loops count [OK]

Common Mistakes:

• Using break level higher than loops
• Assuming break 3 exits 2 loops
• Ignoring PHP fatal error on invalid break level

5.

You want to stop processing nested loops early when a condition is met, but only exit the inner loop sometimes and both loops other times. Which code snippet correctly uses break with levels?

for ($i = 0; $i < 5; $i++) {
    for ($j = 0; $j < 5; $j++) {
        if ($i == 2 && $j == 3) {
            break 2; // exit both loops
        } elseif ($j == 4) {
            break; // exit inner loop only
        }
        echo "$i,$j\n";
    }
}

hard

A. Correct use of break with levels to control loop exit.

B. break 2; should be break 1; to exit both loops.

C. break; cannot be used inside nested loops.

D. break 2; exits only the inner loop.

Solution

1. Step 1: Understand break with levels usage

   break 2; exits two loops, break; exits only the current loop.

2. Step 2: Analyze code logic

   When $i==2 && $j==3, both loops exit with break 2;. When $j==4, only inner loop exits with break;. This matches the requirement.

3. Final Answer:

   Correct use of break with levels to control loop exit. -> Option A

4. Quick Check:

   break n exits n loops, break exits current loop [OK]

Hint: Use break n; for multiple loops, break; for single loop exit [OK]

Common Mistakes:

• Confusing break 2; with break 1;
• Thinking break; exits all loops
• Misusing break levels causing logic errors