How to Read User Input Using Go

Just like printing to the console, reading input from the console with Go is very straightforward. This post aims to teach you just that by going through the steps on how to create a script that outputs 'Hello {name}', where {name} is provided by user input.

To read user input, Go uses a function called 'Scan()', which can be found in the 'fmt' package, so we need to import it. Assuming the code will reside in the function 'main', we get the following starter code:

package main

import "fmt"

func main() {
    // write code here
}

In the main function, we first want to declare a string variable that will store the user's input. We can call this variable 'firstName'.

package main

import "fmt"

func main() {
    var firstName string
}

We can then use the 'Scan()' function to get the user input and store it into the 'firstName' variable. It is important to understand that 'Scan()' takes in a pointer to a variable. This is because Go needs the memory address of the variable in order to assign it a value. Therefore, we write '&firstName' as the parameter.

package main

import "fmt"

func main() {
    var firstName string
    fmt.Scan(&firstName)
}

Lastly, we want to output a greeting to the screen. We can do this with the 'Println()' function. Note that this function is the exact same as 'Print()' but it adds a newline character to the end of the outputted string.

package main

import "fmt"

func main() {
    var firstName string
    fmt.Scan(&firstName)
    fmt.Println("Hello", firstName)
}

With the script finished, you can run it with 'go run main.go'.