Break and Continue Statements in Dart

In Dart, break and continue are control flow statements that allow you to alter the normal flow of loops. They provide mechanisms to manage how loops behave under certain conditions. Understanding how to use these statements can lead to more efficient and readable code.

Break Statement
 

Overview

The break statement is used to exit a loop prematurely, terminating the loop's execution regardless of whether the loop's condition is still true. It can be particularly useful when you want to stop looping based on a specific condition.

Syntax

break;

Example of Break Statement

Here’s an example that demonstrates the use of the break statement within a for loop to find the first number greater than a certain value.

Code:

dart

Copy

void main() {
  for (int i = 1; i <= 10; i++) {
    if (i > 5) {
      print('First number greater than 5 is: $i');
      break; // Exit the loop when i is greater than 5     }
  }
}

Explanation:

• The loop iterates from 1 to 10.
• The if statement checks if i is greater than 5.
• When i becomes 6, it prints the message and executes break, terminating the loop immediately.

Continue Statement
 

Overview

The continue statement is used to skip the current iteration of a loop and continue with the next iteration. This is useful when you want to bypass certain conditions within the loop without terminating the loop entirely.

Syntax

continue;

Example of Continue Statement

Here’s an example that illustrates the use of the continue statement to skip even numbers in a for loop.

Code:

void main() {
  for (int i = 1; i <= 10; i++) {
    if (i % 2 == 0) {
      continue; // Skip the rest of the loop for even numbers     }
    print(i); // Print only odd numbers   }
}

Explanation:

• The loop iterates from 1 to 10.
• The if statement checks if i is even using the modulus operator.
• If i is even, the continue statement is executed, which skips the print(i); statement for that iteration.
• As a result, only odd numbers are printed.

Combined Example: Break and Continue

This example demonstrates both break and continue statements within a single loop.

Code:

void main() {
  for (int i = 1; i <= 10; i++) {
    if (i == 5) {
      print('Breaking the loop at i = $i');
      break; // Exit the loop when i equals 5     }
    if (i % 2 == 0) {
      continue; // Skip even numbers     }
    print(i); // Print only odd numbers   }
}

Explanation:

• The loop iterates from 1 to 10.
• If i equals 5, it prints a message and exits the loop using break.
• If i is even, it skips the current iteration using continue.
• Thus, the output will show odd numbers up to 3, and then it stops when i reaches 5.

Conclusion

The break and continue statements in Dart are powerful tools for controlling loop execution. The break statement allows you to exit a loop immediately when a certain condition is met, while the continue statement lets you skip the current iteration and proceed to the next one. Understanding how to use these statements effectively can help you write clearer and more efficient code in your Dart applications.