Infinite loops in Go - Mini Project: Build & Apply

Infinite loops

📖 Scenario: Imagine you want to create a simple program that keeps printing a message forever, like a clock ticking every second. This helps understand how infinite loops work in programming.

🎯 Goal: Build a Go program that uses an infinite loop to print the message "Tick" repeatedly.

📋 What You'll Learn

Create a variable to hold the message string

Use an infinite for loop to repeat the action

Print the message inside the loop

💡 Why This Matters

🌍 Real World

Infinite loops are used in programs that need to keep running, like servers or clocks.

💼 Career

Understanding infinite loops helps in writing programs that wait for events or run continuously without stopping.

1

DATA SETUP: Create a message variable

Create a variable called message and set it to the string "Tick".

Go

// Your code here

Hint

Use message := "Tick" to create the variable.

2

CONFIGURATION: Prepare for the infinite loop

Keep the variable message and add an infinite for loop below it.

Go

package main

import "fmt"

func main() {
    message := "Tick"
    // Add an infinite for loop below
}

Hint

Use for { to start an infinite loop in Go.

3

CORE LOGIC: Print the message inside the infinite loop

Inside the infinite for loop, use fmt.Println(message) to print the message repeatedly.

Go

package main

import "fmt"

func main() {
    message := "Tick"
    for {
        // Print the message here
    }
}

Hint

Use fmt.Println(message) inside the loop to print the message.

4

OUTPUT: Run the program to see the infinite output

Run the program. It should print Tick repeatedly without stopping.

Go

package main

import "fmt"

func main() {
    message := "Tick"
    for {
        fmt.Println(message)
    }
}

// Run the program to see the output

Hint

The program will print Tick many times. You can stop it manually.

Practice

1. What does the following Go code do?

for { }

easy

A. Runs an infinite loop that never stops

B. Runs a loop 10 times

C. Runs a loop only once

D. Causes a syntax error

Solution

1. Step 1: Understand the loop syntax

   The code uses for { } which is Go's way to write an infinite loop without conditions.

2. Step 2: Analyze loop behavior

   Since there is no break or condition, the loop runs forever without stopping.

3. Final Answer:

   Runs an infinite loop that never stops -> Option A

4. Quick Check:

   for { } means infinite loop [OK]

Hint: for { } always means infinite loop in Go [OK]

Common Mistakes:

• Thinking it runs a fixed number of times
• Assuming it causes a syntax error
• Confusing with loops that have conditions

2. Which of the following is the correct syntax for an infinite loop in Go?

easy

A. for i := 0; i < 10; i++ { }

B. loop forever { }

C. for { }

D. while true { }

Solution

1. Step 1: Review Go loop syntax

   Go does not have a while or loop keyword; infinite loops use for { }.

2. Step 2: Identify correct infinite loop

   for { } uses for { }, which is the correct infinite loop syntax in Go.

3. Final Answer:

   for { } -> Option C

4. Quick Check:

   Go infinite loop syntax = for { } [OK]

Hint: Remember: Go uses for { } for infinite loops [OK]

Common Mistakes:

• Using while or loop keywords (not in Go)
• Confusing for loops with conditions as infinite
• Syntax errors from invalid keywords

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

package main
import "fmt"
func main() {
  count := 0
  for {
    if count == 3 {
      break
    }
    fmt.Println(count)
    count++
  }
}

medium

A. 0 1 2

B. 0 1 2 3

C. Infinite printing of numbers

D. No output

Solution

1. Step 1: Understand loop and break condition

   The loop runs infinitely but breaks when count equals 3.

2. Step 2: Trace output values

   It prints count values 0, 1, 2 then breaks before printing 3.

3. Final Answer:

   0 1 2 -> Option A

4. Quick Check:

   Loop breaks at count==3, prints 0 to 2 [OK]

Hint: Break stops infinite loop at condition [OK]

Common Mistakes:

• Expecting 3 to be printed
• Thinking loop runs forever
• Ignoring break statement

4. Identify the problem in this Go code that causes an infinite loop and fix it:

package main
import "fmt"
func main() {
  i := 0
  for i < 5 {
    fmt.Println(i)
  }
}

medium

A. Add break statement without increment

B. Change for to for { }

C. Remove the loop entirely

D. Add i++ inside the loop to increment i

Solution

1. Step 1: Identify loop condition and variable

   The loop runs while i < 5 but i is never changed inside the loop.

2. Step 2: Fix infinite loop by incrementing i

   Adding i++ inside the loop updates i, allowing the loop to end.

3. Final Answer:

   Add i++ inside the loop to increment i -> Option D

4. Quick Check:

   Increment loop variable to avoid infinite loop [OK]

Hint: Always update loop variable to prevent infinite loops [OK]

Common Mistakes:

• Forgetting to increment loop variable
• Adding break without changing i causes infinite loop
• Changing loop to infinite loop syntax accidentally

5. How can you safely implement an infinite loop in Go that stops after 5 seconds?

hard

A. Use for i := 0; i < 5; i++ { }

B. Use for { } with time.After and break when 5 seconds pass

C. Use while true with a timer

D. Use for { } without any break or condition

Solution

1. Step 1: Understand infinite loop with timeout

   Use for { } for infinite loop and time.After to wait 5 seconds.

2. Step 2: Break loop after 5 seconds

   Inside loop, check if 5 seconds passed and use break to stop loop safely.

3. Final Answer:

   Use for { } with time.After and break when 5 seconds pass -> Option B

4. Quick Check:

   Infinite loop + timer + break = safe stop [OK]

Hint: Combine for { } with timer and break to stop [OK]

Common Mistakes:

• Using invalid while syntax
• Not breaking loop causes infinite run
• Using fixed count loop instead of infinite