Why Continue statement in C++? - Purpose & Use Cases

The Big Idea

What if you could instantly skip unwanted steps in a loop with just one word?

The Scenario

Imagine you are sorting through a long list of numbers to find only the even ones. You write code that checks each number and processes it if it is even. But every time you find an odd number, you still have to write extra code to skip it manually, making your program longer and harder to read.

The Problem

Manually checking each item and writing extra code to skip unwanted cases makes your program bulky and confusing. It's easy to make mistakes, like forgetting to skip some cases, which leads to bugs. Also, the program runs slower because it does unnecessary work before skipping.

The Solution

The continue statement lets you skip the rest of the current loop cycle immediately when a condition is met. This keeps your code clean and focused, avoiding extra nested conditions and making your intentions clear.

Before vs After

✗ Before

for (int i = 0; i < 10; i++) {
  if (i % 2 == 0) {
    // process even number
  }
}

✓ After

for (int i = 0; i < 10; i++) {
  if (i % 2 != 0) continue;
  // process even number
}

What It Enables

It enables writing simpler, cleaner loops that quickly skip unwanted cases, improving readability and reducing errors.

Real Life Example

When processing user input, you can skip invalid entries immediately with continue, so your program only handles valid data without extra checks.

Key Takeaways

Manually skipping cases makes code complex and error-prone.

Continue skips to the next loop iteration instantly.

This leads to cleaner, easier-to-read loops and fewer bugs.

Practice

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

easy

A. It stops the entire loop immediately.

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

C. It exits the current function.

D. It restarts the program from the beginning.

Solution

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

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

2. Step 2: Identify what happens after continue

   After skipping, the loop moves to the next iteration immediately without executing the rest of the loop body.

3. Final Answer:

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

4. Quick Check:

   Continue skips current iteration [OK]

Hint: Continue skips current loop step, not whole loop [OK]

Common Mistakes:

• Thinking continue stops the loop completely
• Confusing continue with break
• Assuming continue exits the function

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

easy

A. continue;

B. continue()

C. continue{}

D. continue[]

Solution

1. Step 1: Recall the syntax of continue in C++

   The continue statement is a keyword and used alone followed by a semicolon.

2. Step 2: Check each option's syntax

   Only continue; is valid. The others use parentheses or braces which are incorrect.

3. Final Answer:

   continue; -> Option A

4. Quick Check:

   Continue ends with semicolon [OK]

Hint: Continue is a keyword, ends with semicolon [OK]

Common Mistakes:

• Adding parentheses after continue
• Using braces or brackets with continue
• Omitting the semicolon

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

for (int i = 1; i <= 5; i++) {
    if (i == 3) continue;
    std::cout << i << " ";
}

medium

A. 1 2 3 4 5

B. 1 2 3 4

C. 1 2 4 5

D. 2 3 4 5

Solution

1. Step 1: Analyze the loop and condition

   The loop runs from 1 to 5. When i == 3, the continue skips printing.

2. Step 2: Determine printed values

   Numbers 1 and 2 print normally. At 3, continue skips printing. Then 4 and 5 print.

3. Final Answer:

   1 2 4 5 -> Option C

4. Quick Check:

   Skip 3, print others [OK]

Hint: Continue skips printing 3, others print [OK]

Common Mistakes:

• Including 3 in output
• Stopping loop at 3
• Printing numbers after 3 incorrectly

4. Identify the error in the following C++ code snippet:

for (int i = 0; i < 5; i++) {
    if (i == 2)
        continue
    std::cout << i << " ";
}

medium

A. No error in the code.

B. Incorrect loop condition.

C. Wrong variable type for i.

D. Missing semicolon after continue statement.

Solution

1. Step 1: Check syntax of continue statement

   The continue statement must end with a semicolon.

2. Step 2: Identify missing semicolon

   In the code, continue is not followed by a semicolon, causing a syntax error.

3. Final Answer:

   Missing semicolon after continue statement. -> Option D

4. Quick Check:

   Continue needs semicolon [OK]

Hint: Always put semicolon after continue [OK]

Common Mistakes:

• Forgetting semicolon after continue
• Assuming continue needs parentheses
• Misreading loop condition as error

5. Consider the following code that sums numbers from 1 to 10 but skips multiples of 3 using continue. What is the final sum?

int sum = 0;
for (int i = 1; i <= 10; i++) {
    if (i % 3 == 0) continue;
    sum += i;
}
std::cout << sum;

hard

A. 52

B. 55

C. 45

D. 50

Solution

1. Step 1: Identify numbers skipped by continue

   Numbers divisible by 3 (3, 6, 9) are skipped and not added to sum.

2. Step 2: Calculate sum of numbers 1 to 10 excluding 3, 6, 9

   Sum 1+2+4+5+7+8+10 = 37 + 15 = 52

3. Final Answer:

   52 -> Option A

4. Quick Check:

   Sum excluding multiples of 3 = 52 [OK]

Hint: Skip multiples of 3, sum others [OK]

Common Mistakes:

• Including multiples of 3 in sum
• Adding all numbers 1 to 10
• Misunderstanding continue effect