What are break and continue statements in Java loops?

Break and Continue Statements in Java Loops

In Java, the break and continue statements are used to control the flow of execution within loop structures, such as for, while, and do-while loops.

Break Statement

The break statement is used to exit a loop prematurely, regardless of whether the loop's termination condition has been met. When the break statement is executed, the control flow immediately jumps out of the loop, and the program continues with the next statement after the loop.

Here's an example of using the break statement in a for loop:

for (int i = 0; i < 10; i++) {
    if (i == 5) {
        break; // Exit the loop when i becomes 5
    }
    System.out.println("Value of i: " + i);
}

Output:

Value of i: 0
Value of i: 1
Value of i: 2
Value of i: 3
Value of i: 4

In this example, the loop would normally execute 10 times, but the break statement is used to exit the loop when the value of i becomes 5.

Continue Statement

The continue statement is used to skip the current iteration of a loop and move on to the next iteration. When the continue statement is executed, the current iteration of the loop is terminated, and the control flow jumps to the next iteration of the loop.

Here's an example of using the continue statement in a for loop:

for (int i = 0; i < 10; i++) {
    if (i % 2 == 0) {
        continue; // Skip the current iteration if i is even
    }
    System.out.println("Value of i: " + i);
}

Output:

Value of i: 1
Value of i: 3
Value of i: 5
Value of i: 7
Value of i: 9

In this example, the loop would normally execute 10 times, but the continue statement is used to skip the current iteration if the value of i is even.

Visualizing Break and Continue with a Mermaid Diagram

Here's a Mermaid diagram that illustrates the flow of execution with break and continue statements in a loop:

graph TD A[Start Loop] --> B[Execute Loop Body] B --> C{Condition Met?} C -- Yes --> D[Continue to Next Iteration] C -- No --> E[Exit Loop] B -- break --> E[Exit Loop] B -- continue --> D[Continue to Next Iteration]

In this diagram, the loop body is represented by the B node. If the loop condition is met (the C node), the control flow continues to the next iteration (D node). If the break statement is encountered, the control flow jumps out of the loop (E node). If the continue statement is encountered, the control flow jumps to the next iteration (D node).

Real-World Examples

Let's consider a few real-world examples to better understand the use of break and continue statements:

Searching for a specific item in a list: Imagine you have a list of items, and you need to find a specific item. You can use the break statement to exit the loop as soon as the item is found, rather than iterating through the entire list.
Validating user input: When prompting a user for input, you might want to use a do-while loop to ensure that the input is valid. If the user enters an invalid input, you can use the continue statement to skip the current iteration and prompt the user again.
Skipping certain iterations in a game loop: In a game loop, you might want to skip certain iterations based on game state or user actions. For example, if the player's character is stunned, you can use the continue statement to skip the current iteration of the game loop and prevent the character from taking any actions.

By understanding the use of break and continue statements, you can write more efficient and flexible Java code that can handle a variety of real-world scenarios.