Java - Statement for Statement

What is for statement?

A for loop statement is an iteration statement.

The general form of a for-loop statement is

for (initialization; condition-expression; expression-list)
      Statement

The initialization, condition-expression, and expression-list are separated by a semicolon.

A for-loop statement consists of four parts:

  • Initialization
  • Condition-expression
  • Statement
  • Expression-list

For example, the following for-loop statement will print all integers between 1 and 10, inclusive:

for(int num = 1; num <= 10; num++)
    System.out.println(num);

Demo

public class Main {
  public static void main(String[] args) {

    for (int num = 1; num <= 10; num++)
      System.out.println(num);/*from   w  w  w .j a  v a2  s .c o  m*/

  }
}

Result

  • First, int num = 1 is executed.
  • Variables declared in the initialization part of the for-loop statement can only be used within that for-loop statement.
  • Then, condition-expression (num <= 10) is evaluated, which is 1 <= 10.
  • It evaluates to true for the first time.
  • Then, the body of for-loop statement is executed, which prints the current value of num.
  • Then, the expression in the expression-list, num++, is evaluated, which increments the value of num by 1 .
  • Now, the value of num becomes 2.
  • Then the condition-expression 2 <= 10 is evaluated, which returns true.
  • Then the current value of num is printed.
  • This process continues until the value of num becomes 10.
  • Then, num++ sets the value of num to 11, and the condition-expression 11 <= 10 returns false
  • Then, the execution of the for-loop statement stops.

Related Topics

Quiz

Example