Go > Core Go Basics > Control Flow > Break and continue

Break and Continue Statements in Go

This snippet demonstrates the usage of break and continue statements within loops in Go, showcasing how they alter the normal flow of execution.

Basic Break Example

This code demonstrates the break statement. The loop iterates from 0 to 9. When i equals 5, the break statement is executed, causing the loop to terminate immediately. The program then proceeds to print "Loop finished."

package main

import "fmt"

func main() {
	for i := 0; i < 10; i++ {
		if i == 5 {
			break // Exit the loop when i is 5
		}
		fmt.Println(i)
	}
	fmt.Println("Loop finished.")
}

Basic Continue Example

This example shows the continue statement. The loop iterates from 0 to 9. When i is even (i.e., i%2 == 0 is true), the continue statement is executed. This causes the current iteration to be skipped, and the loop proceeds to the next iteration. Only odd numbers are printed.

package main

import "fmt"

func main() {
	for i := 0; i < 10; i++ {
		if i%2 == 0 {
			continue // Skip even numbers
		}
		fmt.Println(i)
	}
	fmt.Println("Loop finished.")
}

Concepts behind the Snippets

break and continue are control flow statements used to alter the execution of loops. break terminates the loop prematurely, whereas continue skips the current iteration and proceeds with the next one.

Real-Life Use Case

break can be used to exit a loop when a specific condition is met, such as finding a particular element in a list. continue can be used to skip processing certain elements in a loop based on specific criteria, such as filtering out invalid data.

Best Practices

Use break and continue judiciously. Overuse can make code harder to read and understand. Always ensure the logic behind these statements is clear and well-documented.

Interview Tip

Be prepared to explain the difference between break and continue, and provide examples of when each would be appropriately used. Common interview questions involve tracing code execution with these statements.

When to use them

Use break when you need to completely exit a loop based on a specific condition. Use continue when you need to skip the current iteration of a loop but continue processing the remaining iterations.

Alternatives

In some cases, you can avoid using break and continue by restructuring your loop condition or using boolean flags. However, these alternatives can sometimes make the code more complex.

Pros

break and continue can improve code readability and efficiency by providing a concise way to control loop execution.

Cons

Overuse of break and continue can lead to spaghetti code that is difficult to understand and maintain. It can make the control flow less obvious.

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FAQ

  • What is the difference between break and continue?

    break terminates the loop entirely, while continue only skips the current iteration.
  • Can I use break and continue outside of loops?

    No, break and continue are only valid within loops (for, while (simulated with for in Go), switch). Using them outside of a loop will result in a compilation error.