Go语言实践文章 ｜ 青训营

代码结构：

sorter.go:

`//主程序
// 主程序的package必须是main
package main
 
//import 不用管，IDE会自动增加
import (
"flag"
"os"
"fmt"
"bufio"
"io"
"strconv"
"time"
"sorter/algorithms/qsort"
"sorter/algorithms/bubblesort"
)

flag包快迅解析命令行参数的
var infile *string = flag.String("i", "infile", "File contains values for sorting")
var outfile *string = flag.String("o", "outfile", "File to receive sorted values")
var algorithm *string = 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)
	return
}
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) // 转换字符数组为字符串
	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
}

//程序入口
func main() {
//flag包快迅解析命令行参数的
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 "qsort":
		qsort.QuickSort(values)
	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)
     }
}

bubblesort.go:

// bubblesort.go
package bubblesort
func BubbleSort(values []int) {
flag := true
for i := 0; i <len(values) - 1; i ++ {
	flag = true
	for j := 0; j <len(values) - i - 1; j++ {
		if values[j] > values[j + 1] {
			values[j], values[j + 1] = values[j + 1], values[j]
			flag = false
		} // end if
	} // end for j = ...
	if flag == true {
		break
	}
} // end for i = ...
}

qsort_test.go:

// qsort_test.go
package qsort

import "testing"
func TestQuickSort1(t *testing.T) {
values := []int{5, 4, 3, 2, 1}
QuickSort(values)
if values[0] != 1 || values[1] != 2 || values[2] != 3 || values[3] != 4 ||
	values[4] !=5 {
	t.Error("QuickSort() failed. Got", values, "Expected 1 2 3 4 5")
}
}
func TestQuickSort2(t *testing.T) {
values := []int{5, 5, 3, 2, 1}
QuickSort(values)
if values[0] != 1 || values[1] != 2 || values[2] != 3 || values[3] != 5 ||
	values[4] !=5 {
	t.Error("QuickSort() failed. Got", values, "Expected 1 2 3 5 5")
}
}
func TestQuickSort3(t *testing.T) {
values := []int{5}
QuickSort(values)
if values[0] != 5 {
	t.Error("QuickSort() failed. Got", values, "Expected 5")
}
}

bubble_test.go:

// bubble_test.go
package bubblesort
import "testing"
func TestBubbleSort1(t *testing.T) {
values := []int{5, 4, 3, 2, 1}
BubbleSort(values)
if values[0] != 1 || values[1] != 2 || values[2] != 3 || values[3] != 4 ||
	values[4] !=5 {
	t.Error("BubbleSort() failed. Got", values, "Expected 1 2 3 4 5")
}
}
func TestBubbleSort2(t *testing.T) {
values := []int{5, 5, 3, 2, 1}
BubbleSort(values)
if values[0] != 1 || values[1] != 2 || values[2] != 3 || values[3] != 5 ||
	values[4] !=5 {
	t.Error("BubbleSort() failed. Got", values, "Expected 1 2 3 5 5")
}
}
func TestBubbleSort3(t *testing.T) {
values := []int{5}
BubbleSort(values)
if values[0] != 5 {
	t.Error("BubbleSort() failed. Got", values, "Expected 5")
}
}

运行前准备：

准备“unsorted.dat”文件。

运行过程：

go build sorter/slgorithms/qsort
go build sorter/algorithms/bubblesort
go test sorter/algorithms/qsort
go test sorter/algorithms/bubblesort
go install sorter/algorithms/qsort
go install sorter/algorithms/bubblesort
go build sorter
go install sorter

运行结果：

输出文件：sorted.dat