Go 语言入门

Go 环境安装

访问 Go 官网 https://golang.org，下载对应平台安装包，MacOs 下载 pkg 包一键安装，自动将 go 添加到了环境变量，直接可以使用 go 命令。

第一支 Go 程序：hello, world！

// helloworld.go
package main
import "fmt"

func main() {
  fmt.Println("hello, world!")
}

运行：

两种方法：

该方式只会运行源代码（编译、链接、运行合并为一步），不会产生编译后的可执行文件:

go run helloworld.go

编译、运行分开执行：

go build helloworld.go
./helloworld

Go IDE 安装配置

Go IDE 选择 JetBrains 公司的 Goland：https://www.jetbrains.com/go
Goland 是商业软件，不过可以免费激活：https://gitee.com/pengzhile/jetbrains-agent

主题配置：Material Theam UI + Material Oceanic 配色方案
Material Theam UI 插件安装：GoLand–>Preferences–>Plugins–>Install
Material Oceanic 配色方案：GoLand–>Preferences–>Editor–>Color Scheme–>选择 Material Oceanic

最终效果:

一个较完整的示例程序

package main

import (
	"bufio"
	"flag"
	"fmt"
	"io"
	"os"
	"sorter/sorter/algorithms/bubblesort"
	"strconv"
	"time"
)

var infile = flag.String("i", "infile", "File contains values for sorting")
var outfile = flag.String("o", "outfile", "File to receive sorted values")
var algorithm = flag.String("a", "qsort", "Sort algorithm")

func readValues(infile string) (values []int, err error) {
	file, err := os.Open(infile)
	if err != nil {
		fmt.Println("Failed to open the input file", infile)
	}
	defer file.Close()
	br := bufio.NewReader(file)
	values = make([]int, 0)
	for {
		line, isPrefix, err1 := br.ReadLine()
		if err1 != nil {
			if err1 != io.EOF {
				err = err1
			}
			break
		}
		if isPrefix {
			fmt.Println("A too long line, seems unexpected.")
			return
		}
		str := string(line)
		value, err1 := strconv.Atoi(str)
		if err1 != nil {
			err = err1
			return
		}
		values = append(values, value)
	}
	return
}

func writeValues(values []int, outfile string) error {
	file, err := os.Create(outfile)
	if err != nil {
		fmt.Println("Failed to create the output file ", outfile)
		return err
	}
	defer file.Close()
	for _, value := range values {
		str := strconv.Itoa(value)
		file.WriteString(str + "n")
	}
	return nil
}

func main() {
	flag.Parse()
	if infile != nil {
		fmt.Println("infile=", *infile, "outfile=", *outfile, "algorithm=", *algorithm)
	}
	values, err := readValues(*infile)
	if err == nil {
		t1 := time.Now()
		switch *algorithm {
		case "bubblesort":
			bubblesort.BubbleSort(values)
		default:
			fmt.Println("Sorting algorithm", *algorithm, "is either unknown or unsupported.")
		}
		t2 := time.Now()
		fmt.Println("The sorting process costs", t2.Sub(t1), "to complete.")
		writeValues(values, *outfile)
	} else {
		fmt.Println(err)
	}
}