Break and continue in MATLAB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the break statement do in a MATLAB loop?

The break statement immediately exits the current loop, skipping any remaining iterations.

beginner

What is the purpose of the continue statement in MATLAB?

The continue statement skips the rest of the current loop iteration and moves to the next iteration.

beginner

In which types of loops can you use break and continue in MATLAB?

You can use break and continue in for loops and while loops in MATLAB.

intermediate

What happens if break is used inside nested loops in MATLAB?

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

beginner

How does continue affect the flow inside a MATLAB loop?

When continue is executed, MATLAB skips the remaining code in the current loop iteration and jumps to the next iteration check.

What does the break statement do inside a MATLAB for loop?

A Skips the current iteration and continues with the next

B Stops the loop immediately and exits it

C Restarts the loop from the beginning

D Does nothing

The break statement stops the loop immediately and exits it.

What happens when continue is used inside a MATLAB while loop?

A The loop ends immediately

B The loop pauses

C The loop restarts from the first iteration

D The current iteration is skipped, and the loop continues with the next iteration

The continue statement skips the rest of the current iteration and moves to the next iteration.

Can break be used to exit multiple nested loops at once in MATLAB?

A No, it only exits the innermost loop

B Yes, it exits all loops

C Yes, but only in <code>for</code> loops

D No, it cannot be used in nested loops

The break statement only exits the innermost loop where it is used.

Which of the following is true about continue in MATLAB loops?

A It stops the loop permanently

B It skips the entire loop

C It skips the rest of the current iteration and continues with the next

D It restarts the loop from the beginning

continue skips the rest of the current iteration and continues with the next iteration.

Where can you use break and continue statements in MATLAB?

A In both <code>for</code> and <code>while</code> loops

B Only in <code>while</code> loops

C Only in <code>for</code> loops

D Only in <code>if</code> statements

Both break and continue can be used in for and while loops.

Explain how the break and continue statements control the flow inside MATLAB loops.

Think about what happens when you want to stop or skip parts of a loop.

Describe what happens when break is used inside nested loops in MATLAB.

Consider how loops inside loops behave when interrupted.

Practice

1. What does the break statement do inside a MATLAB loop?

easy

A. Stops the entire loop immediately and exits it.

B. Skips the current iteration and continues with the next one.

C. Restarts the loop from the beginning.

D. Pauses the loop until a condition is met.

Solution

1. Step 1: Understand the purpose of break

   The break statement is used to exit a loop immediately, no matter where it is in the loop.

2. Step 2: Compare with other loop controls

   Unlike continue, which skips only the current iteration, break stops the whole loop.

3. Final Answer:

   Stops the entire loop immediately and exits it. -> Option A

4. Quick Check:

   break = stop loop [OK]

Hint: Break stops loop fully; continue skips one step [OK]

Common Mistakes:

• Confusing break with continue
• Thinking break only skips one iteration
• Believing break restarts the loop

2. Which of the following is the correct syntax to skip the current iteration in a MATLAB for loop?

easy

A. continue;

B. next;

C. break;

D. skip;

Solution

1. Step 1: Identify the statement to skip iteration

   In MATLAB, continue is the keyword used to skip the rest of the current loop iteration and move to the next.

2. Step 2: Check other options

   break exits the loop, skip and next are not valid MATLAB keywords.

3. Final Answer:

   continue; -> Option A

4. Quick Check:

   continue = skip iteration [OK]

Hint: Use continue to skip current loop step [OK]

Common Mistakes:

• Using break instead of continue
• Writing skip or next which are invalid
• Omitting the semicolon (though optional)

3. What will be the output of this MATLAB code?

sum = 0;
for i = 1:5
    if i == 3
        break;
    end
    sum = sum + i;
end
sum

medium

A. 10

B. 3

C. 6

D. 15

Solution

1. Step 1: Trace the loop iterations

   The loop runs i = 1, 2, then at i = 3 the break triggers and loop stops.

2. Step 2: Calculate sum before break

   sum = 0 + 1 + 2 = 3; The addition at i=3 does not happen because break stops loop before sum update.

3. Final Answer:

   3 -> Option B

4. Quick Check:

   Sum before break = 3 [OK]

Hint: Break stops loop before adding i=3 [OK]

Common Mistakes:

• Adding i=3 before break
• Summing all numbers ignoring break
• Confusing break with continue

4. Find the error in this MATLAB code snippet:

for i = 1:5
    if i == 3
        continue
    end
    disp(i)
end

medium

A. Missing semicolon after continue

B. disp(i) will not display 3

C. No error, code runs correctly

D. continue cannot be used inside for loops

Solution

1. Step 1: Check syntax of continue

   In MATLAB, continue does not require a semicolon and is valid inside loops.

2. Step 2: Understand loop behavior

   When i == 3, continue skips disp(i), so 3 is not displayed. This is expected behavior.

3. Final Answer:

   No error, code runs correctly -> Option C

4. Quick Check:

   continue valid in loops [OK]

Hint: Continue works without semicolon in loops [OK]

Common Mistakes:

• Thinking semicolon is mandatory after continue
• Believing continue is invalid in for loops
• Expecting disp to print 3

5. You want to sum numbers from 1 to 10 but skip adding 5 and stop the loop if the sum exceeds 30. Which code correctly uses break and continue?

hard

A. sum = 0;
for i = 1:10
if sum > 30
continue;
elseif i == 5
continue;
end
sum = sum + i;
end

B. sum = 0;
for i = 1:10
if i == 5
break;
elseif sum > 30
continue;
end
sum = sum + i;
end

C. sum = 0;
for i = 1:10
if sum > 30
continue;
elseif i == 5
break;
end
sum = sum + i;
end

D. sum = 0;
for i = 1:10
if i == 5
continue;
end
sum = sum + i;
if sum > 30
break;
end
end

Solution

1. Step 1: Understand conditions order

   We must skip adding 5 (continue when i==5) and stop loop if sum > 30 (break after adding).

2. Step 2: Analyze each option

   sum = 0; for i = 1:10 if i == 5 continue; end sum = sum + i; if sum > 30 break; end end skips 5 before adding, then adds i, then checks sum > 30 to break. This matches requirements.

3. Final Answer:

   C -> Option D

4. Quick Check:

   Skip 5 with continue; break after sum check [OK]

Hint: Continue before add to skip; break after add to stop [OK]

Common Mistakes:

• Breaking when i==5 instead of continuing
• Checking sum > 30 before adding
• Using continue to skip after sum check