Agus Kurniawan - Go Programming by Example

Go Programming by Example

Agus Kurniawan

1st Edition, 2015

Copyright 2015 Agus Kurniawan

* Cover photo is credit to Fajar Ramadhany, Bataviasoft, http://bataviasoft.com/.

** Go logo is taken from https://blog.golang.org/gopher .

This chapter explains introduction of Go. The official web of Go could be found on https://golang.org/. What is Go? Based on information from website, we could know what it is. Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.

Installation of Go application is easy. For Windows and Mac Platform, you download setup file from Go website, http://golang.org/doc/install. Run it and follow installation commands.

The next step is to configure GOROOT path. For Windows platform, you can add GOROOT variable on Environment Variables. For Mac/Linux, you can it on your bash profile.

For Windows platform, you can add GO installation path, for instance my Go installation path is c:/go/bin, into PATH variable on Environment Variables.

After configured, you can verify Go version by typing this command on your Terminal or CMD for Windows.

A sample output can be seen in Figure below, Mac platform.

The output of program on Windows platform.

Basically, you can use any text editor to write Go code. The following is a list of text editor:

• vim
• nano
• Intellij IDEA, https://www.jetbrains.com/idea/
• Sublime text, http://www.sublimetext.com/

A sample screenshot for Intellij IDEA is shown in Figure below.

How to get started with Go? well, it is easy. Firstly, create a folder, called hello.

Then, create a file, called main.go, on the hello folder. Write this code for main.go file.

Save this file. Then, back to your Terminal. You can build and run it.

In this case, it will generate an executable file based on your platform.

A sample program output can be seen in Figure below.

There are a lot of Go packages that you can use. The list of Go packages can seen on this link https://golang.org/pkg/. In this book, we will explore some Go standard packages. We also try to build own Go package.

This chapter explains the basic of Go programming language.

Go language uses "C family" as primary language but we don't write ";" at the end of syntax. Here is the syntax rule:

In this section, we explore how to define a variable and assign its value.

To declare a variable called myvar and data type is data_type1, you can write the following script:

The following is a sample script to declare some variables.

We also can define multiple variables as follows.

Once declared, these variables can be used to store any type data.

Variable that you already declare can be assigned by a value. It can done using the equals sign (=). For example, variable str will assign a string value "Hello World", you would write this:

We also can declare a variable and assign its value.

Another option, we can declare a variable with defining data type using := syntax. Assign it with a value.

For illustration for declaring variables using Go, create a folder, called vardemo. Then, create a file, called main.go.

Write the following script for main.go.

Save this file.

Then, try to build and run it.

A sample output can be seen in Figure below.

You may explain how to work on your code with writing comments. To do it, you can use // and /* */ syntax. Here is sample code:

Go supports the same four basic arithmetic operations such as addition, subtraction, multiplication, and division. For testing, create a folder arithdemo. Then, create a file, called main.go.

The following is the code illustration for basic arithmetic in main.go: