The for loop in Java is a control flow statement that allows you to execute a block of code repeatedly for a fixed number of iterations. It is especially useful when you know in advance how many times you want the loop to run.

The for loop consists of three parts:

• initialization
• condition
• update.

These parts are specified within the loop's header and help manage the loop's behavior.

Syntax

for (initialization; condition; update) {
    // Code block to be executed
}

• Initialization: Executed once at the start; used to set the loop counter.
• Condition: Evaluated before each iteration; if it evaluates to true, the loop body executes.
• Update: Executed at the end of each iteration; typically used to increment or decrement the counter.

Execution Flow of For Loop

• Step 1: The initialization step is executed before the loop starts.
• Step 2: The condition is checked. If it is true, the loop's body executes.
• Step 3: After the code block executes, the update step is performed.
• Step 4: The condition is checked again. If still true, the loop repeats the process. This continues until the condition becomes false.
• Step 5: Once the condition is false, the loop terminates and control moves to the next statement after the loop.

Example 1: Basic for Loop

Below is an example that uses a for loop to print numbers from 1 to 5.

Explanation:

• Initialization: int i = 1 sets the starting value of the loop counter to 1.
• Condition: i <= 5 checks if i is less than or equal to 5 before each loop iteration.
• Update: i++ increments the value of i by 1 after each iteration.
• The loop prints "Number: 1" up through "Number: 5" and then terminates when i becomes 6.

Example 2: Using a for Loop to Sum Numbers

Below is an example that uses a for loop to calculate the sum of the first 5 positive integers.

Explanation:

• Initialization: int i = 1 starts the loop counter at 1.
• Condition: The loop continues as long as i <= 5.
• Update: i++ increases the counter by 1 after each iteration.
• In each iteration, the current value of i is added to sum.
• After finishing the loop, the sum (which is 15) is printed.

The for loop is a powerful construct for repeated execution. By understanding its structure—initialization, condition, and update—you can control the loop's behavior effectively.