Break statement in Go - Mini Project: Build & Apply

Using the Break Statement in Go

📖 Scenario: Imagine you are checking a list of daily temperatures to find the first day when the temperature reaches or exceeds a certain limit. Once you find that day, you want to stop checking further days.

🎯 Goal: You will write a Go program that uses a break statement inside a for loop to stop the loop when the temperature limit is reached.

📋 What You'll Learn

Create a slice of integers called temperatures with the exact values: 23, 25, 28, 30, 32, 29, 27

Create an integer variable called limit and set it to 30

Use a for loop with the variable temp to iterate over temperatures

Inside the loop, use an if statement to check if temp is greater than or equal to limit

Use the break statement to exit the loop when the condition is true

Print the message "Temperature limit reached: X" where X is the temperature that caused the break

💡 Why This Matters

🌍 Real World

Checking sensor data or daily measurements often requires stopping early when a threshold is reached to save time and resources.

💼 Career

Understanding how to control loops with break statements is important for writing efficient programs in many software development and data processing jobs.

1

Create the temperature data

Create a slice of integers called temperatures with these exact values: 23, 25, 28, 30, 32, 29, 27

Go

# Your code here

Hint

Use temperatures := []int{...} to create the slice with the exact numbers.

2

Set the temperature limit

Create an integer variable called limit and set it to 30

Go

package main

func main() {
    temperatures := []int{23, 25, 28, 30, 32, 29, 27}
    // Your code here
}

Hint

Use limit := 30 to create the variable.

3

Use a for loop with break

Use a for loop with the variable temp to iterate over temperatures. Inside the loop, use an if statement to check if temp is greater than or equal to limit. Use the break statement to exit the loop when the condition is true.

Go

package main

func main() {
    temperatures := []int{23, 25, 28, 30, 32, 29, 27}
    limit := 30
    // Your code here
}

Hint

Use for _, temp := range temperatures to loop. Inside, check if temp >= limit and then break.

4

Print the temperature that caused the break

Print the message "Temperature limit reached: X" where X is the temperature that caused the break. Use fmt.Println to display the message.

Go

package main

import "fmt"

func main() {
    temperatures := []int{23, 25, 28, 30, 32, 29, 27}
    limit := 30

    for _, temp := range temperatures {
        if temp >= limit {
            // Your code here
        }
    }
}

Hint

Use fmt.Println("Temperature limit reached:", temp) before the break.

Practice

1. What does the break statement do inside a loop in Go?

easy

A. It pauses the loop for a moment and then continues.

B. It skips the current iteration and moves to the next one.

C. It immediately stops the loop and continues after it.

D. It restarts the loop from the beginning.

Solution

1. Step 1: Understand the role of break in loops

   The break statement is used to exit a loop immediately, stopping any further iterations.

2. Step 2: Compare with other loop controls

   Unlike continue which skips to the next iteration, break stops the loop entirely and moves on.

3. Final Answer:

   It immediately stops the loop and continues after it. -> Option C

4. Quick Check:

   Break stops loop = It immediately stops the loop and continues after it. [OK]

Hint: Break stops loop immediately, no more repeats [OK]

Common Mistakes:

• Confusing break with continue
• Thinking break pauses the loop
• Assuming break restarts the loop

2. Which of the following is the correct syntax to use break inside a for loop in Go?

easy

A. for i := 0; i < 5; i++ { if i == 3 { exit } }

B. for i := 0; i < 5; i++ { if i == 3 { stop } }

C. for i := 0; i < 5; i++ { if i == 3 { continue } }

D. for i := 0; i < 5; i++ { if i == 3 { break } }

Solution

1. Step 1: Identify the correct keyword for stopping a loop

   In Go, break is the keyword used to exit a loop early.

2. Step 2: Check syntax correctness

   for i := 0; i < 5; i++ { if i == 3 { break } } uses break correctly inside an if statement within the for loop.

3. Final Answer:

   for i := 0; i < 5; i++ { if i == 3 { break } } -> Option D

4. Quick Check:

   Correct break syntax = for i := 0; i < 5; i++ { if i == 3 { break } } [OK]

Hint: Use 'break' keyword exactly to stop loops [OK]

Common Mistakes:

• Using 'stop' or 'exit' instead of 'break'
• Confusing 'continue' with 'break'
• Missing curly braces around break

3. What will be the output of this Go code?

for i := 1; i <= 5; i++ {
    if i == 3 {
        break
    }
    fmt.Print(i, " ")
}

medium

A. 1 2 3 4 5

B. 1 2

C. 3 4 5

D. 1 2 3

Solution

1. Step 1: Trace the loop iterations

   The loop starts at i=1 and prints i. When i=3, the break stops the loop immediately.

2. Step 2: Determine printed values before break

   Values printed before break are 1 and 2, then loop stops before printing 3.

3. Final Answer:

   1 2 -> Option B

4. Quick Check:

   Break at 3 stops loop = 1 2 [OK]

Hint: Break stops before printing 3, so only 1 and 2 print [OK]

Common Mistakes:

• Including 3 in output
• Printing all numbers ignoring break
• Confusing break with continue

4. Find the error in this Go code snippet using break:

for i := 0; i < 5; i++ {
    if i == 2 {
        break 2
    }
    fmt.Println(i)
}

medium

A. Using break with a number is invalid in Go.

B. The loop condition is wrong.

C. fmt.Println is not imported.

D. The break statement should be continue.

Solution

1. Step 1: Understand break usage in Go

   Go's break does not accept a number to break multiple loops; it only breaks the closest loop.

2. Step 2: Identify invalid syntax

   Using break 2 causes a syntax error because Go does not support labeled breaks with numbers.

3. Final Answer:

   Using break with a number is invalid in Go. -> Option A

4. Quick Check:

   Break with number invalid = Using break with a number is invalid in Go. [OK]

Hint: Go break never takes a number, only plain break [OK]

Common Mistakes:

• Trying to break multiple loops with a number
• Confusing Go with other languages like JavaScript
• Ignoring syntax errors from break usage

5. Given nested loops, how can you use break to exit only the inner loop in Go?

for i := 1; i <= 3; i++ {
    for j := 1; j <= 3; j++ {
        if j == 2 {
            break
        }
        fmt.Printf("%d,%d ", i, j)
    }
}

What will be the output?

hard

A. 1,1 2,1 3,1

B. 1,1 1,2 2,1 2,2 3,1 3,2

C. 1,1 1,2 2,1 2,2 3,1 3,2 2,2 3,2

D. 1,1 1,2 1,3 2,1 2,2 2,3 3,1 3,2 3,3

Solution

1. Step 1: Understand break in nested loops

   The break inside the inner loop stops only that inner loop when j == 2.

2. Step 2: Trace output for each iteration

   For each i, inner loop prints when j=1, then breaks at j=2, so output is pairs with j=1 only.

3. Final Answer:

   1,1 2,1 3,1 -> Option A

4. Quick Check:

   Break stops inner loop only = 1,1 2,1 3,1 [OK]

Hint: Break stops only closest loop, inner loop ends early [OK]

Common Mistakes:

• Thinking break exits both loops
• Expecting all j values printed
• Confusing break with continue