Continue statement with levels in PHP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of nested loops with continue 2

What is the output of this PHP code snippet?

PHP

<?php
for ($i = 1; $i <= 3; $i++) {
    for ($j = 1; $j <= 3; $j++) {
        if ($j == 2) {
            continue 2;
        }
        echo "$i$j ";
    }
}
?>

A 11 12 13 21 22 23 31 32 33

B 11 13 12 13 21 23 31 33

C 11 13 21 22 23 31 32 33

D 11 21 31

💡 Hint

Remember that continue 2 skips the rest of the current inner and outer loop iteration.

The continue 2 statement skips the rest of the inner loop and also the current iteration of the outer loop. So when j == 2, it skips to the next i value, not printing anything for j == 2.

❓ Predict Output

intermediate

Effect of continue 1 in nested loops

What will this PHP code output?

PHP

<?php
for ($x = 1; $x <= 2; $x++) {
    for ($y = 1; $y <= 3; $y++) {
        if ($y == 2) {
            continue 1;
        }
        echo "$x$y ";
    }
}
?>

A 11 21 31 12 22 32

B 11 13 12 13 21 23

C 11 13 21 23

D 11 12 13 21 22 23

💡 Hint

continue 1 affects only the current loop level.

continue 1 skips the current iteration of the inner loop only, so when y == 2, it skips printing and continues inner loop with next y.

🔧 Debug

advanced

Identify the error in continue statement usage

What error will this PHP code produce?

PHP

<?php
for ($a = 0; $a < 3; $a++) {
    $b = 0;
    while ($b < 3) {
        if ($b == 1) {
            continue 3;
        }
        echo "$a$b ";
        $b++;
    }
}
?>

A Outputs '001 002 101 102 201 202 '

B Fatal error: 'continue' not in the correct loop level

C No output, infinite loop

D Syntax error: unexpected 'continue'

💡 Hint

Check how many nested loops are present and the level used in continue.

continue 3 tries to skip 3 loop levels but only 2 loops exist, causing a fatal error.

❓ Predict Output

advanced

Output with continue 2 inside foreach and for loops

What is the output of this PHP code?

PHP

<?php
$items = ['a', 'b', 'c'];
for ($i = 0; $i < 2; $i++) {
    foreach ($items as $item) {
        if ($item === 'b') {
            continue 2;
        }
        echo "$i$item ";
    }
}
?>

A 0a 1a

B 0a 0c 1a 1c

C 0a 0c 1a

D 0a 1a 1c

💡 Hint

continue 2 skips the current iteration of the outer loop.

When item is 'b', continue 2 skips the rest of foreach and also the current for iteration, so 'c' is never printed for that i.

🧠 Conceptual

expert

Understanding continue with levels in complex nested loops

Consider this PHP code with three nested loops. Which statement about the effect of continue 2; inside the innermost loop is true?

PHP

<?php
for ($x = 1; $x <= 2; $x++) {
    foreach ([10, 20] as $y) {
        $z = 0;
        while ($z < 3) {
            if ($z == 1) {
                continue 2;
            }
            echo "$x$y$z ";
            $z++;
        }
    }
}
?>

A continue 2 skips the rest of the while loop and the current foreach iteration, moving to next foreach value

B continue 2 skips only the current while iteration, continuing the while loop

C continue 2 skips the entire for loop iteration, moving to next x

D continue 2 causes a syntax error because it is inside a while loop

💡 Hint

Remember that continue with a number skips that many nested loops.

continue 2 skips the current and next outer loop. Here, inside while, continue 2 skips while and foreach iteration, moving to next foreach value.

Practice

1.

What does the continue statement do inside a loop in PHP?

easy

A. It skips the rest of the current loop iteration and moves to the next iteration.

B. It stops the entire loop immediately.

C. It restarts the whole program.

D. It pauses the loop for a moment.

Solution

1. Step 1: Understand the role of continue in loops

   The continue statement tells the loop to skip the remaining code in the current iteration.

2. Step 2: What happens after continue?

   The loop immediately moves to the next iteration, not stopping the entire loop.

3. Final Answer:

   It skips the rest of the current loop iteration and moves to the next iteration. -> Option A

4. Quick Check:

   continue skips current iteration [OK]

Hint: Remember: continue skips current iteration only [OK]

Common Mistakes:

• Thinking continue stops the whole loop
• Confusing continue with break
• Assuming continue pauses the program

2.

Which of the following is the correct syntax to skip the current iteration of the outer loop in nested loops using continue in PHP?

for ($i = 0; $i < 3; $i++) {
    for ($j = 0; $j < 3; $j++) {
        if ($j == 1) {
            // What continue statement skips outer loop iteration?
        }
    }
}

easy

A. continue 2;

B. continue 1;

C. continue;

D. continue 3;

Solution

1. Step 1: Understand nested loop levels

   There are two loops: outer ($i) and inner ($j). To skip outer loop iteration, we use continue 2;.

2. Step 2: Apply continue n; syntax

   continue 2; skips the current iteration of the second enclosing loop (outer loop).

3. Final Answer:

   continue 2; -> Option A

4. Quick Check:

   continue 2; skips outer loop iteration [OK]

Hint: Use continue n; where n = loop level to skip [OK]

Common Mistakes:

• Using continue without number skips inner loop only
• Using continue 1; which skips inner loop only
• Using continue 3; which is invalid here

3.

What will be the output of the following PHP code?

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

medium

A. 11 13 12 22 32

B. 11 21 31

C. 11 12 13 21 22 23 31 32 33

D. 11 13 21 23 31 33

Solution

1. Step 1: Analyze the nested loops and continue 2;

   When $j == 2, continue 2; skips the rest of the inner and outer loop iteration, moving to next $i.

2. Step 2: Trace output for each iteration

   For $i=1: $j=1 prints '11 ', $j=2 triggers continue 2; skips to $i=2.
   For $i=2: $j=1 prints '21 ', $j=2 triggers continue 2; skips to $i=3.
   For $i=3: $j=1 prints '31 ', $j=2 triggers continue 2; loop ends.

3. Final Answer:

   11 21 31 -> Option B

4. Quick Check:

   continue 2 skips outer loop iteration [OK]

Hint: continue 2 skips outer loop iteration immediately [OK]

Common Mistakes:

• Assuming continue 2 skips only inner loop
• Expecting all combinations printed
• Ignoring that continue 2 skips outer loop iteration

4.

Find the error in this PHP code snippet that tries to skip the outer loop iteration when $j == 2:

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

medium

A. The continue statement should be break 3; instead.

B. There is no error; the code runs fine.

C. The echo statement is inside the wrong loop.

D. Using continue 3; causes a fatal error because only 2 loops exist.

Solution

1. Step 1: Count the nested loops

   There are only 2 loops: outer ($i) and inner ($j).

2. Step 2: Check the continue level

   continue 3; tries to skip 3 levels, but only 2 exist, causing a fatal error.

3. Final Answer:

   Using continue 3; causes a fatal error because only 2 loops exist. -> Option D

4. Quick Check:

   continue n must not exceed loop depth [OK]

Hint: continue n; must not exceed nested loop count [OK]

Common Mistakes:

• Using continue with number larger than loop depth
• Confusing continue with break
• Ignoring PHP fatal error on invalid continue level

5.

You want to print all pairs (i, j) for i and j from 1 to 3, but skip printing pairs where j == 2 and also skip the entire outer loop iteration if i == 2. Which code snippet correctly uses continue with levels to achieve this?

hard

A. for ($i = 1; $i <= 3; $i++) {
if ($i == 2) continue;
for ($j = 1; $j <= 3; $j++) {
if ($j == 2) continue;
echo "($i,$j) ";
}
}

B. for ($i = 1; $i <= 3; $i++) {
for ($j = 1; $j <= 3; $j++) {
if ($j == 2) continue;
if ($i == 2) continue 2;
echo "($i,$j) ";
}
}

C. for ($i = 1; $i <= 3; $i++) {
for ($j = 1; $j <= 3; $j++) {
if ($i == 2) continue 2;
if ($j == 2) continue;
echo "($i,$j) ";
}
}

D. for ($i = 1; $i <= 3; $i++) {
for ($j = 1; $j <= 3; $j++) {
if ($i == 2 || $j == 2) continue 2;
echo "($i,$j) ";
}
}

Solution

1. Step 1: Understand the requirements

   Skip printing pairs where j == 2, and skip entire outer loop iteration if i == 2.

2. Step 2: Analyze each option

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

   skips i == 2 outer loop correctly but skips j == 2 only in inner loop.
   

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

   tries to continue 2 inside inner loop after j check, but order is wrong.
   

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

   first skips outer loop iteration if i == 2 using continue 2;, then skips j == 2 in inner loop.
   

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

   skips outer loop iteration if either i == 2 or j == 2, which is incorrect.

3. Final Answer:

   Option C correctly uses continue 2; to skip outer loop when i == 2 and continue to skip j == 2. -> Option C

4. Quick Check:

   Use continue 2; to skip outer loop inside inner loop [OK]

Hint: Place continue 2; before continue for inner loop skip [OK]

Common Mistakes:

• Skipping outer loop for wrong conditions
• Using continue 2; incorrectly for inner loop skip
• Combining conditions incorrectly causing wrong skips