for loop example in java

The for Loop:

A for loop is a repetition control structure that allows you to efficiently write a loop that needs to execute a specific number of times.

A for loop is useful when you know how many times a task is to be repeated.

Syntax:

The syntax of a for loop is:

for(initialization; Boolean_expression;Increment or decrement)
{
   //Statements
}

Here is the flow of control in a for loop:

The initialization step is executed first, and only once. This step allows you to declare and initialize any loop control variables. You are not required to put a statement here, as long as a semicolon appears.

Next, the Boolean expression is evaluated. If it is true, the body of the loop is executed. If it is false, the body of the loop does not execute and flow of control jumps to the next statement past the for loop.

After the body of the for loop executes, the flow of control jumps back up to the update statement. This statement allows you to update any loop control variables. This statement can be left blank, as long as a semicolon appears after the Boolean expression.

The Boolean expression is now evaluated again. If it is true, the loop executes and the process repeats itself (body of loop, then update step, then Boolean expression). After the Boolean expression is false, the for loop terminates.

Example:

if use Microsoft Notepad save Testoffor.java

public class Testoffor {

   public static void main(String args[]) {

      for(int y = 20; y < 30; y = y+1) {
         System.out.print("value of y : " + y );
         System.out.print("\n");
      }
   }
}

compile with jdk: javac Testoffor.java
run:java Testoffor

This would produce the following result:

value of y : 20
value of y : 21
value of y : 22
value of y : 23
value of y : 24
value of y : 25
value of y : 26
value of y : 27
value of y : 28
value of y : 29