Loops in Java

In this tutorial, we will learn about different types of loops in Java. We will cover the basics of for, while, and do-while loops.

What is a Loop

A loop is a control flow statement that allows code to be executed repeatedly based on a condition.

Loops

Java supports three types of loops: for loops, while loops, and do-while loops.

For Loop

A for loop is used when the number of iterations is known before entering the loop. The syntax for the for loop is:

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

While Loop

A while loop is used when the number of iterations is not known beforehand. The syntax for the while loop is:

while (condition) {
    // Code block to be executed
}

Do-While Loop

A do-while loop is similar to a while loop, but it guarantees that the code block will be executed at least once. The syntax for the do-while loop is:

do {
    // Code block to be executed
} while (condition);

Example 1: Printing Numbers from 1 to 10 using For Loop

  1. Declare an integer variable i.
  2. Use a for loop to print numbers from 1 to 10.

Java Program

public class Main {
    public static void main(String[] args) {
        for (int i = 1; i <= 10; i++) {
            System.out.print(i + " ");
        }
    }
}

Output

1 2 3 4 5 6 7 8 9 10

Example 2: Printing Numbers from 1 to 5 using While Loop

  1. Declare an integer variable i and initialize it to 1.
  2. Use a while loop to print numbers from 1 to 5.

Java Program

public class Main {
    public static void main(String[] args) {
        int i = 1;
        while (i <= 5) {
            System.out.print(i + " ");
            i++;
        }
    }
}

Output

1 2 3 4 5

Example 3: Printing Numbers from 1 to 3 using Do-While Loop

  1. Declare an integer variable i and initialize it to 1.
  2. Use a do-while loop to print numbers from 1 to 3.

Java Program

public class Main {
    public static void main(String[] args) {
        int i = 1;
        do {
            System.out.print(i + " ");
            i++;
        } while (i <= 3);
    }
}

Output

1 2 3