Java break and continue Statements

In Java, the break and continue statements are used to alter the flow of control in loops. They provide mechanisms to exit loops prematurely or skip certain iterations, respectively. Understanding how to use these statements effectively can help in creating more flexible and efficient loops.

1. The break Statement

The break statement is used to exit from a loop (or switch statement) prematurely, regardless of whether the loop’s condition is true or false. It immediately terminates the loop and transfers control to the statement following the loop.

Syntax

break;

Example of break in a for Loop

public class Main {
    public static void main(String[] args) {
        for (int i = 0; i < 10; i++) {
            if (i == 5) {
                break;  // Exit the loop when i is 5
            }
            System.out.println(i);
        }
    }
}

Output:

0
1
2
3
4

In this example, the break statement is executed when i equals 5, causing the loop to exit early. The output includes numbers from 0 to 4, and the loop terminates before reaching 5.

Example of break in a while Loop

public class Main {
    public static void main(String[] args) {
        int i = 0;

        while (i < 10) {
            if (i == 5) {
                break;  // Exit the loop when i is 5
            }
            System.out.println(i);
            i++;
        }
    }
}

Output:

0
1
2
3
4

Similar to the for loop example, the break statement exits the while loop when i equals 5.

2. The continue Statement

The continue statement is used to skip the current iteration of a loop and proceed to the next iteration. Unlike the break statement, continue does not exit the loop; it only skips the remaining code in the current iteration and reevaluates the loop’s condition.

Syntax

continue;

Example of continue in a for Loop

public class Main {
    public static void main(String[] args) {
        for (int i = 0; i < 10; i++) {
            if (i % 2 == 0) {
                continue;  // Skip even numbers
            }
            System.out.println(i);
        }
    }
}

Output:

1
3
5
7
9

In this example, the continue statement skips the System.out.println(i) line for even numbers (when i % 2 == 0). As a result, only odd numbers are printed.

Example of continue in a while Loop

public class Main {
    public static void main(String[] args) {
        int i = 0;

        while (i < 10) {
            i++;
            if (i % 2 == 0) {
                continue;  // Skip even numbers
            }
            System.out.println(i);
        }
    }
}

Output:

1
3
5
7
9

Here, the continue statement skips the System.out.println(i) for even numbers and continues with the next iteration of the loop.

3. break and continue in Nested Loops

In nested loops, the break statement exits the innermost loop, while the continue statement affects only the current loop level. To exit multiple levels of nested loops, you can use labeled breaks.

Example of break in Nested Loops

public class Main {
    public static void main(String[] args) {
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (i == 1 && j == 1) {
                    break;  // Exits the inner loop when i is 1 and j is 1
                }
                System.out.println("i = " + i + ", j = " + j);
            }
        }
    }
}

Output:

i = 0, j = 0
i = 0, j = 1
i = 0, j = 2
i = 1, j = 0

The break statement exits the inner loop when i is 1 and j is 1. The outer loop continues to execute.

Example of Labeled break Statement

To break out of multiple nested loops, use a labeled break.

public class Main {
    public static void main(String[] args) {
        outerLoop: // Labeled block
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (i == 1 && j == 1) {
                    break outerLoop;  // Breaks out of both loops
                }
                System.out.println("i = " + i + ", j = " + j);
            }
        }
    }
}

Output:

i = 0, j = 0
i = 0, j = 1
i = 0, j = 2
i = 1, j = 0

The labeled break exits both the inner and outer loops when i is 1 and j is 1.

Example of Labeled continue Statement

Labeled continue is used to skip the current iteration of an outer loop from within an inner loop.

public class Main {
    public static void main(String[] args) {
        outerLoop: // Labeled block
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (i == 1 && j == 1) {
                    continue outerLoop;  // Skips to the next iteration of the outer loop
                }
                System.out.println("i = " + i + ", j = " + j);
            }
        }
    }
}

Output:

i = 0, j = 0
i = 0, j = 1
i = 0, j = 2
i = 1, j = 0
i = 2, j = 0
i = 2, j = 1
i = 2, j = 2

Here, the labeled continue skips the rest of the inner loop when i is 1 and j is 1, and proceeds to the next iteration of the outer loop.

4. Summary

• break Statement: Exits from the current loop or switch statement immediately.
• continue Statement: Skips the remaining code in the current loop iteration and proceeds to the next iteration.
• Nested Loops: break exits the innermost loop; continue affects only the current loop level.
• Labeled break and continue: Useful for breaking out of or continuing specific levels of nested loops.

Using break and continue statements effectively helps in controlling the flow of loops and can simplify the logic in certain scenarios.