Go – Read String Input from Console

In this tutorial, we will learn how to read a string input from the console in the Go programming language (Golang). Reading input from the console is a common operation for interactive programs.

We’ll explore a simple way to accomplish this using the fmt.Scanln function, along with a detailed explanation and examples.

Syntax to Read String Input

The basic syntax to read a string input in Go is:

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fmt.Scanln(&variable)

Here, variable is the string variable where the input from the console will be stored. The ampersand (&) is used to pass the memory address of the variable to the Scanln function.

Example Program to Read String Input

In this example, we prompt user to input a string, read the string using Scanln(), and finally print the read string to output.

Program – example.go

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package main

import "fmt"

func main() {
    // Declare a string variable to hold user input
    var input string

    // Prompt the user
    fmt.Print("Enter a string: ")

    // Read input from the console
    fmt.Scanln(&input)

    // Print the input back to the console
    fmt.Println("You entered:", input)
}

Explanation of Program

  1. Declare a Variable: A variable of type string is declared to store the user input.
  2. Prompt the User: The fmt.Print function is used to display a message prompting the user to enter a string.
  3. Read the Input: The fmt.Scanln function reads the input typed by the user and stores it in the variable. The & operator is used to pass the address of the variable.
  4. Print the Input: The entered string is printed back to the console using the fmt.Println function.

Output

This example demonstrates how to read a single string input from the user via the console and display it back.

Handling Multiple Words

The fmt.Scanln function reads input up to the first whitespace. If you need to read an entire line, including spaces, you can use the bufio package:

Program – example.go

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package main

import (
    "bufio"
    "fmt"
    "os"
)

func main() {
    // Create a reader to read input
    reader := bufio.NewReader(os.Stdin)

    // Prompt the user
    fmt.Print("Enter a full line: ")

    // Read the full line of input
    input, _ := reader.ReadString('\n')

    // Print the input back to the console
    fmt.Println("You entered:", input)
}

Output

The bufio.NewReader with ReadString is useful for reading input containing spaces or special characters.