Break statement in C - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the break statement do in C?

The break statement immediately exits the nearest enclosing loop or switch statement, skipping the rest of its body.

beginner

In which control structures can you use the break statement?

You can use break inside for, while, do-while loops, and switch statements.

intermediate

What happens if you use break inside nested loops?

The break statement only exits the innermost loop where it is used, not all loops.

beginner

Can break be used outside loops or switch statements?

No, using break outside loops or switch causes a compile-time error.

beginner

Example: What will this code print?

for(int i = 0; i < 5; i++) {
  if(i == 3) break;
  printf("%d ", i);
}

It will print: 0 1 2
The loop stops when i equals 3 because of the break.

What does the break statement do inside a loop?

A Stops the loop immediately and exits it

B Skips the current iteration and continues

C Restarts the loop from the beginning

D Does nothing special

The break statement immediately stops the loop and exits it.

Where can you NOT use the break statement?

A Outside any loop or <code>switch</code>

B Inside a <code>switch</code> statement

C Inside a <code>while</code> loop

D Inside a <code>for</code> loop

Using break outside loops or switch causes a compile error.

If you have nested loops, which loop does break exit?

A None of the loops

B The outermost loop

C All loops at once

D The innermost loop where <code>break</code> is used

break exits only the innermost loop it is inside.

What will happen if break is used inside a switch statement?

A It restarts the <code>switch</code>

B It exits the entire program

C It exits the <code>switch</code> and continues after it

D It causes a syntax error

break exits the switch statement and continues with the code after it.

What will this code print?

int i = 0;
while(i < 5) {
  if(i == 2) break;
  printf("%d ", i);
  i++;
}

A 0 1 2 3 4

B 0 1

C 2 3 4

D Nothing

The loop stops when i is 2 due to break, so it prints 0 and 1.

Explain how the break statement affects loops and switch statements in C.

Think about what happens when you want to stop a loop early.

Describe a real-life situation where using a break statement in a loop would be helpful.

Imagine looking for something in a list and stopping once you find it.

Practice

1.

What does the break statement do inside a loop in C?

easy

A. It immediately exits the loop and continues with the code after the loop.

B. It pauses the loop for a moment and then continues.

C. It restarts the loop from the beginning.

D. It skips the current iteration and moves to the next one.

Solution

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

   The break statement is designed to stop the loop immediately when executed.

2. Step 2: Identify what happens after break

   After breaking, the program continues with the first statement after the loop block.

3. Final Answer:

   It immediately exits the loop and continues with the code after the loop. -> Option A

4. Quick Check:

   Break stops loop immediately = A [OK]

Hint: Break exits loop immediately, no more iterations [OK]

Common Mistakes:

• Confusing break with continue
• Thinking break pauses the loop
• Assuming break restarts the loop

2.

Which of the following is the correct syntax to use break inside a for loop in C?

for(int i = 0; i < 5; i++) {
    if(i == 3) {
        ?
    }    printf("%d ", i);
}

easy

A. exit;

B. continue;

C. break;

D. stop;

Solution

1. Step 1: Recall the keyword to exit loops

   In C, break; is the correct statement to exit loops immediately.

2. Step 2: Check syntax correctness

   Only break; is a valid C keyword; others like exit; or stop; are invalid here.

3. Final Answer:

   break; -> Option C

4. Quick Check:

   Correct break syntax = D [OK]

Hint: Use 'break;' to exit loops, not 'exit;' or 'stop;' [OK]

Common Mistakes:

• Using 'exit;' instead of 'break;'
• Confusing 'continue;' with 'break;'
• Missing semicolon after break

3.

What will be the output of the following C code?

int i;
for(i = 0; i < 5; i++) {
    if(i == 2) {
        break;
    }
    printf("%d ", i);
}

medium

A. 0 1

B. 0 1 2

C. 2

D. 0 1 2 3 4

Solution

1. Step 1: Trace loop iterations until break

   The loop starts i=0, prints 0; i=1, prints 1; when i=2, break triggers and loop stops.

2. Step 2: Determine printed values

   Only 0 and 1 are printed before break stops the loop.

3. Final Answer:

   0 1 -> Option A

4. Quick Check:

   Break at i=2 stops loop, prints 0 1 [OK]

Hint: Break stops loop before printing i=2 [OK]

Common Mistakes:

• Including value at break condition in output
• Confusing break with continue
• Assuming loop runs fully

4.

Identify the error in this C code snippet using break:

int i = 0;
if(i == 0) {
    break;
}

medium

A. Variable i not declared

B. Missing semicolon after break

C. No error, code is correct

D. break used outside loop or switch statement

Solution

1. Step 1: Check where break is used

   The break statement is inside an if but not inside a loop or switch.

2. Step 2: Recall break usage rules

   In C, break must be inside loops or switch; using it outside causes a compile error.

3. Final Answer:

   break used outside loop or switch statement -> Option D

4. Quick Check:

   Break outside loop/switch = error [OK]

Hint: Break only inside loops or switch [OK]

Common Mistakes:

• Using break inside if without loop
• Forgetting break requires semicolon (not the main error here)
• Assuming break works anywhere

5.

Consider the nested loops below. What will be the output?

for(int i = 1; i <= 3; i++) {
    for(int j = 1; j <= 3; j++) {
        if(j == 2) {
            break;
        }
        printf("%d%d ", i, j);
    }
}

hard

A. 13 12 11

B. 11 21 31

C. 11 12 13 21 22 23 31 32 33

D. 11 12 21 22 31 32

Solution

1. Step 1: Analyze inner loop behavior with break

   Inner loop runs j=1 to 3, but breaks when j==2, so only j=1 prints.

2. Step 2: Trace all iterations

   For i=1, prints 11; i=2 prints 21; i=3 prints 31; each inner loop stops after j=1.

3. Final Answer:

   11 21 31 -> Option B

4. Quick Check:

   Break stops inner loop at j=2, prints only j=1 per i [OK]

Hint: Break stops inner loop early, only first inner print per outer loop [OK]

Common Mistakes:

• Assuming inner loop prints all j values
• Confusing break effect on outer loop
• Including j=2 prints