Coming from other languages, the first thing you'll notice about Go is that it's obsessed with simplicity—sometimes to a point that feels aggressive. The best example of this is the loop. In Go, there is no while. There is no do-while. There is only for.

Now, don't let that panic you. The for keyword is a Swiss Army knife; it handles every looping scenario you'll ever encounter. To show you how, let's build a simple "Retry Mechanism." Imagine we're trying to connect to a flaky external API. We don't want to give up on the first failure, but we can't try forever or we'll hang the whole system.

Starting with the classic counter

Most of us start here. If you know C, Java, or JavaScript, this will look familiar. We want to try our connection exactly three times. I'll set up a simple loop with an initialization, a condition, and a post-statement.

package main

import "fmt"

func main() {
    for i := 1; i <= 3; i++ {
        fmt.Printf("Attempt %d: Connecting to API...\n", i)
        // Imagine a network call happens here
    }
    fmt.Println("Done trying.")
}

This is the "standard" loop. It's predictable and clean. But in the real world, we usually don't want to run exactly three times regardless of the outcome. We want to stop as soon as the connection succeeds.

Simulating a "while" loop

Since Go doesn't have a while keyword, we just omit the initialization and the post-statement. If you only provide a condition, Go treats it exactly like a while loop in other languages. I'll rewrite this to keep trying as long as we haven't succeeded and haven't hit our limit.

attempts := 0
success := false

for attempts < 3 && !success {
    attempts++
    fmt.Printf("Attempt %d: Trying to connect...\n", attempts)
    
    if attempts == 2 { // Let's pretend it works on the second try
        success = true
        fmt.Println("Connected!")
    }
}

I personally prefer this style for retry logic. It reads more like a sentence: "For as long as attempts are less than three and we haven't succeeded, keep going."

The infinite loop and my classic mistake

Sometimes you don't know the exit condition upfront, or the exit logic is too complex for a single line. In those cases, you use the "forever" loop: just the word for with no condition at all. You then handle the exit using a break statement.

I actually tripped over this during a project a few months ago. I was writing a polling loop to check for a file on a disk. I wrote something like this:

// WARNING: This is the mistake I made
for {
    fmt.Println("Checking for file...")
    if fileExists() {
        fmt.Println("Found it!")
        // I forgot to put the 'break' here!
    }
}

I ran the code, and it worked perfectly—until the file actually appeared. Then, my terminal turned into a blur of "Found it!" messages, printing thousands of times per second. I'd created an infinite loop because I forgot to tell Go to actually stop once the condition was met. It's a silly mistake, but it happens to the best of us when we're moving too fast.

Here is the corrected version. You always need a way out when using a bare for loop:

for {
    fmt.Println("Checking for file...")
    if fileExists() {
        fmt.Println("Found it!")
        break // This is the magic word that stops the loop
    }
    
    // I'd also add a sleep here so I don't melt my CPU
}

Choosing the right tool

So, which one should you use? If you have a fixed range, go with the three-component loop. If you're waiting for a specific state to change, the "while-style" loop is your friend. If you're building a background worker or a listener that runs until the program terminates (or hits a complex break condition), use the bare for.

📋 Practical Task

Exercise: Build a Limited-Attempt Password Validator

Create a program that simulates a login system. The user should have a maximum of 5 attempts to enter the correct password (you can hardcode the correct password as a string variable).

• Use a for loop to track the number of attempts.
• Inside the loop, simulate a password check.
• If the password is correct, print "Access Granted" and use break to exit the loop immediately.
• If the password is incorrect, print "Incorrect password" and the number of attempts remaining.
• If the loop finishes all 5 iterations without a correct password, print "Account Locked: Too many failed attempts."