Go Learning Path - Module 1: Hello World & Basic Concepts

go教程目录

Module 1: Hello World & Basic Concepts

Module 2: Variables, Data Types, and Constants

Module 3: Functions, Methods, and Packages

Module 4: Control Structures (if/else, loops)

Module 5: Arrays, Slices, and Maps Arrays

Module 6: Structs and Interfaces

Module 7: Pointers and Memory Management

Module 8: Concurrency with Goroutines and Channels

Module 9: Error Handling and Defer/Panic/Recover

Module 10: Advanced Topics - Testing and Standard Library

Welcome to Go programming! Go (also known as Golang) is a statically typed, compiled programming language designed at Google. This module introduces you to the basics of Go.

Hello World Program

Let's start with the classic "Hello, World!" program:

  
package main
  

  
import "fmt"
  

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

Explanation:

• package main - Every Go program starts with a package declaration. The main package is special - it defines a standalone executable program.

• import "fmt" - Imports the fmt package which provides formatted I/O functions.

• func main() - The entry point function that gets executed when the program runs.

• fmt.Println() - Prints the string followed by a newline.

How to Run Go Programs

Save your code in a file ending with .go extension (e.g., hello.go) and run:

  
go run hello.go
  

To compile and generate an executable:

  
go build hello.go
  
./hello        # On Unix/Linux/Mac
  
hello.exe      # On Windows
  

Package Declaration

Every Go program belongs to a package. Packages help organize and reuse code:

  
package main    // For executable programs
  

  
// Or for libraries
  
package utils   // A reusable package named 'utils'
  

Import Statements

You can import multiple packages:

  
package main
  

  
import (
  
    "fmt"
  
    "math"
  
)
  

  
func main() {
  
    fmt.Println("Square root of 16 is:", math.Sqrt(16))
  
}
  

Comments

Go supports single-line and multi-line comments:

  
// This is a single-line comment
  

  
/*
  
This is a
  
multi-line comment
  
*/
  

Exercises

1. Modify the hello world program to print your name.

2. Create a program that prints multiple lines using multiple Println statements.

3. Experiment with the fmt.Print() function to see how it differs from fmt.Println().

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Next: Module 2: Variables, Data Types, and Constants