How to Use fmt.Println in Go: Simple Print Output Guide

Use fmt.Println in Go to print text or variables to the console with a newline at the end. Import the fmt package, then call fmt.Println() with the values you want to display.

Syntax

The basic syntax of fmt.Println is simple. You write fmt.Println() and put the values you want to print inside the parentheses, separated by commas. It automatically adds a space between values and a newline at the end.

• fmt: The package that contains the print functions.
• Println: The function that prints with a newline.
• Arguments: Values to print, like strings, numbers, or variables.

go

fmt.Println(value1, value2, ...)

Example

This example shows how to print a simple message and a number using fmt.Println. It demonstrates printing text and variables together.

go

package main

import "fmt"

func main() {
    name := "Alice"
    age := 30
    fmt.Println("Hello, my name is", name)
    fmt.Println("I am", age, "years old")
}

Output

Hello, my name is Alice
I am 30 years old

Common Pitfalls

Some common mistakes when using fmt.Println include forgetting to import the fmt package, missing commas between values, or expecting no spaces between printed values.

Also, fmt.Println always adds a space between arguments and a newline at the end, so if you want no spaces or no newline, use other functions like fmt.Print or fmt.Printf.

go

package main

import "fmt"

func main() {
    // Wrong: missing comma between values
    // fmt.Println("Hello" "World") // This causes a compile error

    // Right: add comma
    fmt.Println("Hello", "World")

    // Wrong: forgetting to import fmt
    // fmt.Println("Hello") // This causes an error
}

Output

Hello World

Quick Reference

• fmt.Println(): Prints values with spaces and adds a newline.
• fmt.Print(): Prints values without adding a newline.
• fmt.Printf(): Prints formatted strings using verbs like %s, %d.
• Always import fmt to use these functions.

Key Takeaways

Always import the fmt package to use fmt.Println.

Use fmt.Println to print values separated by spaces with a newline at the end.

Separate multiple values with commas inside fmt.Println parentheses.

fmt.Println automatically adds spaces between values and a newline after printing.

For no newline or custom formatting, consider fmt.Print or fmt.Printf.