Part 1: Hello Gopher

What is Go or Golang?

Go is an expressive, concise, clean, and efficient programming language. Go is a fast, statically typed, compiled language but feels like a dynamically typed, interpreted language. At times it resembles C in terms of Syntax.

Installing Go

We are not going to discuss specific steps of installation as it is already mentioned on https://golang.org/. In this series, we are going to use https://replit.com/ for writing our programs.

Write a program to print "Hello Gopher" on stdout

package main
import "fmt"

func main() {
  fmt.Println("Hello Gopher")
}

//=> go run main.go
Hello Gopher

Save the above as main.go and run go run main.go to see the output.

Let's understand what each specific statement means.

1. package main

   • usually, in computer science a package is a collection of shared functions/methods.
   • package keyword in Go is used to name a package.
   • main package in Go tells the Go compiler that the package should compile as an executable program instead of a shared library.
   • the main function in the package main is the entry point of every Go executable program.

2. import "fmt"

   • import keyword with a <package name> tells the compiler that the program is going to use an external package for using the functions defined in that package.
   • import "fmt" imports fmt package that contains methods to interact with stdin & stdout. Package fmt implements formatted I/O with functions analogous to C's printf and scanf.

3. func main() {...}

   • func keyword is used to declare a function in Go. As already said, every program in Go starts with main function. Function contains statements wrapped inside {}.

4. fmt.Println("Hello Gopher")

   • we already know that fmt is a package containing functions that can be used in any other package. fmt.Println("Hello Gopher") invokes Println function with "Hello Gopher" as a parameter. Println stands for print line which prints and adds a line break at the end.

How to run a Go program

• go run main.go compiles and runs a Go program.
• go build -o <output-filename> compiles a Go program and creates an executable output file with the name specified for -o.

That is it for this part, in the next part we will solve few simple mathematical problems in Go and get to know about DataTypes and Variables in Go.