How to write a simple Go program?

Go (also known as Golang) is a beautiful, modern and efficient programming language. It has easy-to-use syntax and rich libraries for network and concurrent programming. In this article, we will discuss how to write a simple Go program.

1. Installing Go

Before we start writing Go programs, we need to install Go first. The Go official website provides a variety of installation methods: binaries are provided on Windows, macOS and Linux. You can visit https://golang.org/dl/ website to download.

After successful installation, you can check the version of Go by entering the following command on the command line:

go version

2. Writing Hello World program

Let's write a Hello World program to output "Hello, World!" on the command line.

First, open your favorite text editor, create a new file in it, and save it as "hello.go". Then, enter the following in that file:

package main

import "fmt"

func main() {
    fmt.Println("Hello, World!")
}

Let’s explain this code line by line:

• package main declares a package called "main " package, it is a special package, every Go program has at least one main package. This package tells the compiler where it can find the main function.
• import "fmt"Imports a package named "fmt", which contains functions output to the console.
• func main() is the entry point of the program. Program execution starts from here.
• fmt.Println("Hello, World!")Use the Println function in the fmt package to output "Hello, World!" on the console.

Save and close the file. Next, we need to run the program using the terminal as follows:

1. In the command line, change to the directory where the file is located.
2. Enter the following command:

go run hello.go

3. You should see the following output on the console:

Hello, World!

Congratulations, you have successfully written your first Go program!

3. Variables and Types

When writing any program, it is crucial to understand how to declare and use variables. Variables can be used to store data, such as numbers, strings, etc.

The following code demonstrates how to declare variables and assign them to different data types:

package main

import "fmt"

func main() {
    var i int = 72
    var f float64 = 3.14
    var b bool = true
    var s string = "Hello, World!"

    fmt.Printf("i = %d, f = %f, b = %t, s = %s", i, f, b, s)
}

The output should be:

i = 72, f = 3.140000 , b = true, s = Hello, World!

The above program uses the keyword var to declare variables, and then assigns them to different data types. The fmt.Printf function is used to format and output variable values. %d is used to output integers, %f is used to output floating point numbers, %t is used to output Boolean values ​​(true or false), and %s is used to output strings.

4. Operators and flow control

Go supports various operators and flow control structures. For example, the following program demonstrates if/else statements in Go:

package main

import "fmt"

func main() {
    num := 3

    if num % 2 == 0 {
        fmt.Println("Even")
    } else {
        fmt.Println("Odd")
    }
}

The output will be:

Odd

This program checks if the num variable Is an even number, if so, output "Even", otherwise output "Odd".

In addition to if/else statements, Go also supports switch statements, for loops, break and continue statements, etc.

5. Conclusion

In this article, we introduced how to write a simple Go program. We discussed how to install Go, declare variables, use operators, and flow control structures. Go is a powerful programming language suitable for network and concurrent programming. We encourage you to start with this simple program before starting to write more advanced programs.

The above is the detailed content of How to write a simple Go program?. For more information, please follow other related articles on the PHP Chinese website!