Break and continue in MATLAB - Step-by-Step Execution

Concept Flow - Break and continue

Start Loop

↓

Check Condition

↓

Check Break?

Yes↓

Break Loop

↓

Check Continue?

Yes↓

Skip Rest of Loop

↩Back to Start Loop

The loop starts and checks the condition. If false, it exits. If true, it checks if break or continue applies. Break exits loop immediately; continue skips to next iteration.

Execution Sample

MATLAB

for i = 1:5
  if i == 3
    break;
  elseif i == 2
    continue;
  end
  disp(i);
end

Loop from 1 to 5, skip printing 2, stop loop when i is 3.

Execution Table

Iteration	i	Condition i==3?	Condition i==2?	Action	Output
1	1	False	False	Print i	1
2	2	False	True	Continue (skip print)
3	3	True	False	Break loop
-	-	-	-	Loop ends	-

💡 Loop ends because break is triggered at i=3

Variable Tracker

Variable	Start	After 1	After 2	After 3	Final
i	-	1	2	3	-

Key Moments - 2 Insights

Why does the loop stop at i=3 even though the loop range is 1 to 5?

Because the break statement triggers when i equals 3, immediately exiting the loop as shown in execution_table row 3.

Why is the number 2 not printed even though the loop reaches i=2?

Because the continue statement skips the rest of the loop body for i=2, so disp(i) is not executed, as shown in execution_table row 2.

Visual Quiz - 3 Questions

Look at the execution table, what is the output when i equals 2?

A 2 is printed

B Nothing is printed

C Loop breaks

D Error occurs

💡 Hint

Check the Action and Output columns for iteration 2 in the execution_table.

At which iteration does the loop stop executing?

A After iteration 1

B After iteration 2

C After iteration 3

D After iteration 5

💡 Hint

Look at the Condition i==3? and Action columns in the execution_table.

If the break statement was removed, what would happen to the output?

A Only 1 would print

B Numbers 1, 3, 4, 5 would print

C Numbers 1 to 5 would print except 2

D No numbers would print

💡 Hint

Without break, loop runs full range; continue skips printing 2 as shown in variable_tracker and execution_table.

Concept Snapshot

Break and continue in MATLAB loops:
- break exits loop immediately
- continue skips current iteration rest
- Use inside if conditions
- Controls loop flow clearly
- Helps skip or stop early

Full Transcript

This example shows a MATLAB for loop from 1 to 5. When i equals 2, the continue statement skips printing i, so 2 is not shown. When i equals 3, the break statement stops the loop immediately, so the loop ends early. The execution table tracks each iteration's variable i, conditions checked, actions taken, and output. The variable tracker shows how i changes each step. Key moments clarify why the loop stops early and why 2 is not printed. The visual quiz tests understanding of these steps. The concept snapshot summarizes break and continue usage in MATLAB loops.

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