Loop with break in Rust - Step-by-Step Execution

Concept Flow - Loop with break

Start Loop

↓

Execute Loop Body

↓

Check break condition

↓

Exit Loop

The loop runs repeatedly until the break condition is true, then it stops immediately.

Execution Sample

Rust

let mut count = 0;
loop {
    if count == 3 {
        break;
    }
    count += 1;
}

This code counts from 0 up, stopping the loop when count reaches 3.

Execution Table

Step	count	Condition (count == 3)	Action	Loop Status
1	0	false	count += 1 -> 1	continue
2	1	false	count += 1 -> 2	continue
3	2	false	count += 1 -> 3	continue
4	3	true	break	exit

💡 At step 4, count == 3 is true, so break stops the loop.

Variable Tracker

Variable	Start	After 1	After 2	After 3	Final
count	0	1	2	3	3

Key Moments - 2 Insights

Why does the loop stop exactly when count is 3?

Because at step 4 in the execution_table, the condition count == 3 is true, triggering the break which immediately exits the loop.

What happens if the break condition never becomes true?

The loop would run forever because break is never called, so the loop never exits (infinite loop).

Visual Quiz - 3 Questions

Look at the execution_table, what is the value of count at step 3?

A 1

B 2

C 3

D 0

💡 Hint

Check the 'count' column in the execution_table row for step 3.

At which step does the loop stop running?

A Step 4

B Step 3

C Step 2

D Step 5

💡 Hint

Look at the 'Loop Status' column in the execution_table to find when it says 'exit'.

If the break condition was changed to count == 5, what would happen at step 4?

A Loop breaks at step 4

B count resets to 0

C Loop continues because condition is false

D Error occurs

💡 Hint

Refer to the 'Condition' column logic in the execution_table and imagine count == 3 vs count == 5.

Concept Snapshot

Rust loop with break:
loop {
  if condition {
    break;
  }
  // code
}
The loop runs until break stops it immediately when condition is true.

Full Transcript

This example shows a Rust loop that counts up from zero. Each time the loop runs, it checks if count equals 3. If yes, it breaks out of the loop. Otherwise, it adds 1 to count and repeats. The execution table tracks count and the condition each step. When count reaches 3 at step 4, the break stops the loop. Variables change as count goes from 0 to 3. Beginners often wonder why the loop stops exactly at 3 and what happens if break never triggers. The quiz asks about count values and when the loop exits, reinforcing understanding of break behavior.