Golang While Loop

A while loop is a looping construct that allows you to run a block of code as long as a condition is true. Unlike a for loop where you determine the number of times a block should run beforehand, in a while loop, it is useful when you do not have pre-define iterations.

For example, for a while, we can use a loop to continuously prompt the user for a password until they get it right. Since the number of tries can range from 1 to infinity, a while loop is the best choice for such an operation.

But the question is, how do we create a for loop in go?

In this short guide, you will learn how to implement a while loop in go using a for loop.

Go Create While Loop

Unlike other programming languages, Go does not provide a keyword to construct a while loop. Instead, we get a for-loop construct.

One unique feature about a for loop in go is that it has three individual components, which are optional. This allows you to modify a for loop to build other looping constructs such as a while loop.

To create a while loop using the for keyword, we skip the variable initialization and the post statement and specify the loop condition.

Consider the syntax below

for condition {
// run
}

We use the for keyword in the syntax above, followed by a Boolean condition. While the condition is true, we continuously execute the code inside the curly braces.

Once the condition becomes false, we terminate the loop.

Go While Loop – Examples

Let us look at a few examples to understand better how to create a while loop in go.

Example 1

Consider the example below that uses a while loop to count from 1 to 5.

package main
import "fmt
func main() {
i := 1
for i <= 5 {
fmt.Println(i)
i++
}
}

In the example above, we start by creating a variable i and assigning it the value of 1. Next, we create a for loop to check if the value of i is less than or equal to 5. While true, we print the value of i and increment the value by 1.

The above condition evaluates to:

while (i <= 5) {
}

in other programming languages.

Once we run the code, we should get an output as shown:

1
2
3
4
5

Example 2

The example below continuously asks the user for the password as long as the provided password is incorrect.

package main
import (
"fmt"
)
var password string
func main() {
for password != "password" {
fmt.Println("Enter the password: ")
fmt.Scanln(&password)
}
}

If we run the code above, we should see the prompt until we input the correct password as shown:

$ go run while.go
=> Enter the password:
wrong
=> Enter the password:
correct
=> Enter the password:
stop
=> Enter the password:
password

Closing

This guide taught you how to create a while loop using the for-loop construct. Thank you for reading.