Continue statement in Javascript - Time & Space Complexity

Time Complexity: Continue statement

O(n)

Understanding Time Complexity

Let's see how using the continue statement affects the time it takes for a loop to run.

We want to know how skipping some steps changes the total work done.

Scenario Under Consideration

Analyze the time complexity of the following code snippet.

for (let i = 0; i < n; i++) {
  if (i % 2 === 0) {
    continue;
  }
  console.log(i);
}
    

This code loops from 0 to n-1 but skips printing even numbers using continue.

Identify Repeating Operations

Identify the loops, recursion, array traversals that repeat.

• Primary operation: The for loop runs from 0 to n-1.
• How many times: The loop runs exactly n times, but continue skips some steps inside.

How Execution Grows With Input

Even though some steps are skipped, the loop still checks each number once.

Input Size (n)	Approx. Operations
10	10 checks, about 5 prints
100	100 checks, about 50 prints
1000	1000 checks, about 500 prints

Pattern observation: The total steps grow directly with n, even if some actions inside are skipped.

Final Time Complexity

Time Complexity: O(n)

This means the time grows in a straight line with the size of the input, no matter how many times we skip inside.

Common Mistake

[X] Wrong: "Using continue makes the loop run faster and reduces time complexity."

[OK] Correct: The loop still runs n times; skipping steps inside doesn't reduce the number of loop cycles.

Interview Connect

Understanding how control statements like continue affect loops helps you explain code efficiency clearly and confidently.

Self-Check

What if we replaced continue with an if statement that wraps the inner code instead? How would the time complexity change?

Practice

1. What does the continue statement do inside a loop in JavaScript?

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 from the beginning.

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

Solution

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

   The continue statement skips the remaining code inside the current loop iteration.

2. Step 2: Identify what happens after continue

   After skipping, the loop moves directly to the next iteration without stopping the whole 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 step [OK]

Hint: Remember: continue skips current step, break stops loop [OK]

Common Mistakes:

• Confusing continue with break
• Thinking continue stops the loop
• Believing continue restarts the program

2. Which of the following is the correct syntax to use continue inside a for loop in JavaScript?

easy

A. continue[];

B. continue;

C. continue loop;

D. continue()

Solution

1. Step 1: Recall the syntax of continue

   The continue statement is used alone followed by a semicolon.

2. Step 2: Check each option for syntax correctness

   continue; uses continue; which is correct. Options A, B, and C use invalid syntax.

3. Final Answer:

   continue; -> Option B

4. Quick Check:

   Correct syntax is continue; [OK]

Hint: Use continue as a statement, no parentheses or brackets [OK]

Common Mistakes:

• Adding parentheses after continue
• Using continue with labels incorrectly
• Adding brackets or other symbols

3. What will be the output of the following code?

for (let i = 1; i <= 5; i++) {
  if (i === 3) continue;
  console.log(i);
}

medium

A. 1 2 3 4 5

B. 3 4 5

C. 1 2 4 5

D. 1 2

Solution

1. Step 1: Analyze the loop and condition

   The loop runs from 1 to 5. When i is 3, continue skips the console.log.

2. Step 2: Determine which numbers are printed

   Numbers 1, 2, 4, and 5 are printed. Number 3 is skipped.

3. Final Answer:

   1 2 4 5 -> Option C

4. Quick Check:

   continue skips 3, prints others [OK]

Hint: Skip printing when continue runs, others print [OK]

Common Mistakes:

• Including the skipped number in output
• Confusing continue with break
• Ignoring the condition inside the loop

4. Find the error in this code snippet:

for (let i = 0; i < 5; i++) {
  if (i = 2) continue;
  console.log(i);
}

medium

A. The assignment operator (=) is used instead of comparison (===) in the if condition.

B. continue cannot be used inside for loops.

C. console.log should be before the if statement.

D. The loop condition should be i <= 5.

Solution

1. Step 1: Identify the if condition mistake

   The condition uses i = 2 which assigns 2 to i instead of comparing.

2. Step 2: Understand the effect of assignment in if

   Assignment returns 2 (truthy), so continue runs every time, causing an infinite loop or skipping all logs.

3. Final Answer:

   The assignment operator (=) is used instead of comparison (===) in the if condition. -> Option A

4. Quick Check:

   Use === for comparison, not = [OK]

Hint: Use === for comparison inside if, not = [OK]

Common Mistakes:

• Using = instead of === in conditions
• Thinking continue is invalid in for loops
• Misplacing console.log inside loop

5. You want to print all numbers from 1 to 10 except multiples of 3 using a for loop and continue. Which code correctly achieves this?

hard

A. for(let i=1; i<=10; i++) { if(i % 3 === 0) return; console.log(i); }

B. for(let i=1; i<=10; i++) { if(i % 3 !== 0) continue; console.log(i); }

C. for(let i=1; i<=10; i++) { if(i % 3 === 0) break; console.log(i); }

D. for(let i=1; i<=10; i++) { if(i % 3 === 0) continue; console.log(i); }

Solution

1. Step 1: Understand the goal

   We want to skip printing numbers divisible by 3, so use continue when i % 3 === 0.

2. Step 2: Check each option

   for(let i=1; i<=10; i++) { if(i % 3 === 0) continue; console.log(i); } correctly skips multiples of 3 and prints others. for(let i=1; i<=10; i++) { if(i % 3 !== 0) continue; console.log(i); } skips non-multiples, wrong. for(let i=1; i<=10; i++) { if(i % 3 === 0) break; console.log(i); } uses break, stops loop early. for(let i=1; i<=10; i++) { if(i % 3 === 0) return; console.log(i); } uses return, invalid in this context.

3. Final Answer:

   for(let i=1; i<=10; i++) { if(i % 3 === 0) continue; console.log(i); } -> Option D

4. Quick Check:

   continue skips multiples of 3, prints rest [OK]

Hint: Use continue to skip unwanted cases inside loop [OK]

Common Mistakes:

• Using break instead of continue
• Reversing the condition logic
• Using return inside loops incorrectly