Loop execution flow in Java - Step-by-Step Execution

Concept Flow - Loop execution flow

Initialize loop variable i=0

↓

Check condition i < 3?

No→EXIT loop

Yes↓

Execute loop body

↓

Update loop variable i = i + 1

↩Back to condition check

The loop starts by setting a variable, checks if it meets a condition, runs the loop body if yes, updates the variable, and repeats until the condition is false.

Execution Sample

Java

for (int i = 0; i < 3; i++) {
    System.out.println(i);
}

This code prints numbers 0, 1, and 2 by looping while i is less than 3.

Execution Table

Step	i value	Condition (i < 3)	Action	Output
1	0	true	Print i=0	0
2	1	true	Print i=1	1
3	2	true	Print i=2	2
4	3	false	Exit loop

💡 i reaches 3, condition 3 < 3 is false, loop stops

Variable Tracker

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

Key Moments - 2 Insights

Why does the loop stop when i equals 3?

Because the condition i < 3 becomes false at step 4, so the loop exits as shown in the execution_table row 4.

When is the value of i updated during the loop?

i is updated after the loop body runs, before the next condition check, as seen between steps 1-2, 2-3, and 3-4 in the variable_tracker.

Visual Quiz - 3 Questions

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

A 2

B 3

C 1

D 0

💡 Hint

Check the 'i value' column in execution_table row 3.

At which step does the loop condition become false?

A Step 2

B Step 3

C Step 4

D Step 1

💡 Hint

Look at the 'Condition (i < 3)' column in execution_table where it changes to false.

If the loop condition was changed to i <= 3, how many times would the loop run?

A 3 times

B 4 times

C 2 times

D 5 times

💡 Hint

Consider the variable_tracker and how the condition affects loop continuation.

Concept Snapshot

for (int i = 0; i < limit; i++) {
  // loop body
}

1. Initialize i
2. Check condition (i < limit)
3. Run body if true
4. Increment i
5. Repeat until condition false

Full Transcript

This example shows how a for loop runs in Java. It starts by setting i to 0. Then it checks if i is less than 3. If yes, it prints i and increases i by 1. This repeats until i is 3, when the condition fails and the loop stops. The execution_table shows each step with i's value, condition result, action, and output. The variable_tracker follows i's changes. Key moments explain why the loop stops and when i updates. The quiz tests understanding of i's value at steps, when the loop ends, and effects of changing the condition.