练习题

　　

Golang练习题

　　HelloWorld

func main() {
    fmt.Println("HelloWorld")
}

　　99乘法表

func main() {
    for i := 1;i<10;i++ {
        for j := 1;i<=i;j++ {
            fmt.Println("%d * %d = %d\t",j,i,j*i)
        }
    fmt.Println()
}

　　质数判断

func justfy(a int) bool {
    for i := 2;i<a;i++ {
        if a % i == 0{
            return false
        }
    }
    return true
}
func main() {
    for i:=2;i<100;i++ {
        if justfy(i) == true {
            fmt.Printf("[%d] is prime\n",i}
        }
    }
}

　　水仙花数，1的立方+5的立方+3的立方=153

func shuixianhua(a int) bool {
    first := a%10
    second := (a/10)%10
    third := (a/100)%10
    sum := first*first*first+second*second*second+third*third*third
    if sum == a{
        return true
    }
    reutrn false
}
func main() {
    for i := 100;i<1000;i++{
        if shuixianhuashu(i) == true{
            fmt.Printf("[%d]是水仙花数\n",i)
        }
    }
}

　　字符统计:：输入一行字符，统计出英文字母、空格、数字和其他字符的个数

func test(str string) (charCount,numCount,spaceCount,otherCount int) {
    uftChars := []rune(str)
    for i:= 0;i<len(uftChars);i++ {
        if uftChars[i] >= 'a' && uftChars[i] <= 'z' || uftChars[i] >= 'A' && uftChars[i] <= 'Z' {
            charCount++
            continue
        }
        if uftChars[i] >= '0' && uftChars[i] <='9' {
            numChount++
            continue
        }
        if uftChars[i] == ' '{
            spaceConut++
            continue
        }
        otherCount++}
    }
    return
}
func main() {
    var str string = "dksjfhk   我123+---"
    carCount,numCount,spCount,other := test(str)
    fmt.Printf("字母有%d,数字有%d,空格有%d,其他有%d", charCount, numCount, spCount, other)
}

　　插入排序

func inser_sort(a [8]int) [8]int {
    for i:=1;i<len(a);i++ {
        for j:= i;j>0;j-- {
            if a[j] <a[j-1] {
                a[j],a[j-1] = a[j-1],a[j]
            } else {
                break
            }
        }
    }
    return a
}
func main() {
    var i [8]int = [8]int{8,3, 2, 9, 4, 6, 10, 0}
    j := inser_sort(i)
    fmt.Println(i)    //[8,3, 2, 9, 4, 6, 10, 0]
    fmt.Println(j)    //[0,2,3,4,6,8,9,10]
}

　　选择排序

func selet_sort(a [8]int) [8]int {
    for i:=0;i<len(a);i++ {
        for j:= i+1;j<len(a);j++ {
            if a[j] < a[i] {
                [i],a[j] = a[j],a[i]
            }
        }
    }
    return a
}
func main() {
    var i [8]int = [8]int{8, 3, 2, 9, 4, 6, 10, 0}
    j := select_sort(i)
    fmt.Println(i)    //[8, 3, 2, 9, 4, 6, 10, 0]
    fmt.Println(j)    //[0,2,3,4,6,8,9,10]
}

　　斐波那锲数列

//递归
func fab(n int) int{
    if n<=1 {
        return 1
    }
    return fab(n-1) + fab(n-2)
}
func main() {
    for i :=0;i<10;i++ {
        n:= fab(i)
        fmt.Println(n)
    }
}

　　冒泡排序

func select_sort(a [8]int) [8]int{
    for i:= 0;i<len(a);i++ {
        for j:=0;j<len(a)-i-1;j++ {
            if a[j]>a[j+1]{
                a[j],a[j+1] = a[j+1],a[j]
            }
        }
    }
    return a
}
func main() {
    var i [8]int = [8]int{8, 3, 2, 9, 4, 6, 10, 0}
    j := select_sort{i}
    fmt.Println(i)
    fmt.Println(j)
}

　　数组元素之和

func main() {
    a := [...]int{1,3,5,6,8}
    b := 0
    for _,value := range a {
        b += value
    }
    fmt.Println(b)
}

　　数组中和为给定值的两个元素的下标：数组[1,3,4,8,7]中找出和为8的下标分别是(0,4)和(1,2)

func main() {
    a := [...]int{1,2,3,4,5,8,4,4,2}
    for i:=0;i<len(a);i++ {
        for j:= i+1;j<len(a);j++ {
            if a[i]+a[j] == 8 {
                fmt.Printf("(%d,%d)的和等于8\n",i,j)
            }
        }
    }
}

　　切片程序输出

func main() {
    var sa = make([]string,5,10)
    for i := 0;i<5;i++ {
        sa = append(sa,fmt.Sprintf("%v",i))
    }
    fmt.Println(sa)
}    //[     0,1,2,3,4,5,6,7,8,9]

　　sort排序包对数据进行排序

func main() {
    var a [5]int = [5]int{1,4,2,5,6}
    sort.Ints(a[:])    //Ints表示整型
    fmt.Println(a)
    var b [5]string = [5]string{"ac","ed","sd","fg"}
    sort.Strings(b[:])    //Strings表示字符串类型
    fmt.Println(b)
}    //Float64表示浮点型

　　统计字符串中每个单词出现的次数

//端口
func test(str string) map[string]int {
    var result mapp[string]int = make(map[string]int,128)
    words := strings.Split(str," "}
    for _,v := range words {
        count,ok := result[v]
        if !ok {
            result[v] = 1
        } else {
            result[v] = count+1
        }
    }
    return result
}
func main() {
    var str = "how do ou do?"
    result := test(str)
    fmt.Printf("result%v\n",result)
}

//文件
type CharCount struct {
    ChCount INT
    NumCount int
    SpaceCount int
    OtherCount int
}
func main() {
    file,err := os.Open("c:/test.log")
    if err != nil {
        fmt.Println("read file err:",err)
        return
    }
    defer file.Close()
    var count CharCount
    reader := bufio.NewReader(file)
    for {
        str,err := reader.ReadString('\n')
        if err == io.EOF {
            break
        }
        if err == ! nil {
            fmt.printf("read file failed,err:%v",err)
            break
        }
        runeArr := []rune(str)
        for _,v := range runeArr {
            switch {
            case v > ='a' && v<='z':
                fallthrouth    //满足这个条件的无条件执行下一个case内容
            case v >= 'A'&&v<='Z':
                count.ChCount++
            case v==' '||v=='\t':
                count.SpaceCount++
            case v>='0'&&v<='9':
                count.NumCount++
            default:
                count.OtherCount++
            }
        }
    }
    fmt.Printf("char count:%d\n",count.ChCount)
    fmt.Printf("num count:%d\n",count.NumCount)
    fmt.Printf("space count:%d\n",count.SpaceCount)
    fmt.Printf("other count:%d\n",count.OtherCount)
}

　　存储学生信息

//学生有id、年龄、分数、需要方便通过id查到对应学生的信息
func test() {
    var stuMap map[int]map[string]interface{}
    stuMap = make(map[int]map[string]interface{},16)
    var id = 1
    var name = "stu01"
    var score = 79.3
    var age = 19
    value,ok := stuMap[id]
    if !ok {
        value = make(map[string]interface{},8)
    }
    value["id"] = id
    value["name"] = name
    value["score"] = score
    value["age"] = age
    stuMap[id] = value
    fmt.Printf("stuMap:%v\n",stuMap)    //stuMap:map[1:mao[age:19 id:1 name:stu01 score:79.3]]    带#表示要输出类型
    fmt.Printf("stuMap:%#v\n",stuMap)    //stuMap:mao[int]mao[string]interface{}{1:map[string]interface{}{"age":18,"id":1,"name":"stu01","score":79.3}}
    for i:= 0;i<10;i++ {
        value,ok := stuMap[i]
        if !ok {
            value = make{map[string]interface{},8)
        }
        value["name"] = fmt.Sprintf("stu%d",i)
        value["id"] = i
        value["score"] = rand.Float32()*100.0
        value["age"] = rand.Intn(100)
        stuMap[i] = vaue
    }
    fmt.Println()
    for k,v := range stuMap {
        fmt.Printf("id=%d stu info = %#v\n",k,v)
    }
}

　　struct链表：单向链表

//尾部添加
type Student struct {
    Name string
    Age int
    Score float64
    next *Student
}
func trans(p *Student) {
    for p!= nil {
        fmt.Println(*p)
        p = p.next
    }
    fmt.Println()
}
func test() {
    var head Student
    head.Name = "yang"
    head.Age = 19
    head.Score 100.00
    var tail = &head
    for i:=0;i<5;i++ {
        stu := &Student{
            Name : fmt.Sprintf("stu%d",i),
            Age:rand.Intn(100)
            Score:rand.Float64() *100,
        }
        tail.next = stu
        tail = stu
    }
    trans(&head)
}

//头部添加
type Stident struct {
    Name string
    Age int
    Score float64
    next *Student
}
func trans(p *Student) {
    for p!= nil {
        fmt.Println(*p)
        p = p.next
    }
    fmt.Println()
}
func test() {
    var head *Student = &Student{}
    head.Name = "hua"
    head.Age = 18
    head.Score = 100
    for i := 0;i<5;i++ {
        stu := Student{
            Name : fmt.Printf("stu%d",i),
            Age : rand.Intn(100),
            Score:rand.Float64() *100,
        }
        stu.next = head
        head = &stu
    }
    trans(head)
}

　　defer练习

func f1() int{
    x:= 5
    defer func() {
        x++
    }()
    return x
}
func f2() (x int) {
    defer func() {
        x++
    }()
    return 5
}
func f3() (y int) {
    x := 5
    defer func() {
        x++
    }()
    return x
}
func f4() (x int) {
    defer func(x int) {
        x++
    }(x)
    return 5
}
func main () {
    fmt.Println(f1())    //5
    fmt.Println(f2())    //6
    fmt.Println(f3())    //5
    fmt.Println(f4())    //5
}

　　并发引起的闭包

//问题
var wg sync.WaitGroup
func main() {
    wg.Add(1000)
    for i :=0;i<1000;i++ {
        go func() {
            fmt.Println(hello",i)
            wg.Done()
        }()
    }
    wg.Wait()
}    //会有很多重复的1000，匿名函数中i存在调用外部变量的情况产生闭包

//解决
var wg synv.WaitGroup
func main() {
    wg.Add1000）
    for i:=0;i<1000;i++ {
        go func(i int) {
            fmt.Println("hello",i)
            wg.Done()
        }(i)
    }
    wg.Wait()
}    //把i传进去就会解决嗲用外部变量的问题

　　简单聊天机器人

package main
import (
    "bufio"
    "fmt"
    "os"
    "strings"
)
func main() {
    //从标准输入读取数据
    inputReader := bufio.NewReader(os.Stdin)
    fmt.Println("Please input your name：")
    //读取数据直到遇见\n位置
    input, err := inputReader.ReadString('\n')
    if err != nil {
        fmt.Printf("An error occurred:%s\n", err)
        //异常错误后退出
        os.Exit(1)

    } else {
        //用切片操作删除最后的\n
        name := input[:len(input)-1]
        fmt.Printf("Hello,%s!What can i di for you?\n", name)
    }
    for {
        input, err = inputReader.ReadString('\n')
        if err != nil {
            fmt.Printf("An error occurred:%s\n", err)
            continue
        }
        input = input[:len(input)-1]
        //全部转换为小写
        input = strings.ToLower(input)
        switch input {
        case "":
            continue
        case "nothing", "bye":
            fmt.Println("Bye!")
            //正常退出
            os.Exit(0)
        default:
            fmt.Println("Sorry,I didn't catch you.")

        }
    }
}

　　二分查

//存在多个重复元素的切片中查找元素并返回最大的角标
func BinarySearch(s []int, k int) int {
    lo, hi := 0, len(s)-1
    for lo <= hi {
        m := (lo + hi) >> 1
        if s[m] < k {
            lo = m + 1
        } else if s[m] > k {
            hi = m - 1
        } else {
            if s[m+1] == k {
                lo = lo + 1
            } else {
                return m
            }
        }
    }
    return -1
}
func main() {
    s := []int{0, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 6, 6, 6, 7, 7, 7, 8, 9}
       fmt.Println(BinarySearch(s, 1))
}

　　股票购买手续费计算

package main

import "fmt"

func In(n,z float32,tuichu *bool){
	//买入时需要的费用
	if *tuichu == false {	//判断如果变量为false，则退出到主函数
		return
	}
	var nn,mm,zz float32
	fmt.Println("请输入买入几手股份(1手=100股)")
	fmt.Scanf("%f\n",&nn)
	fmt.Println("请输入买入价格")
	fmt.Scanf("%f\n",&mm)
	nn = nn*100		//将几手转为几百股
	zz = nn*mm		//买入需要的总价
	//计算手续费
	if zz*0.0003<5 {
		zz = zz+5
		zz = zz*0.00002+zz
		shou := zz*0.00002+5
		fmt.Printf("手续费：%.3f\n",shou)
	}else {
		zz = zz*0.0003+zz
		zz = zz*0.00002+zz
		shou := zz*0.0003+zz*0.00002
		fmt.Printf("手续费：%.3f\n",shou)
	}
	//买入后持仓
	z = z+zz
	n = n+nn
	fmt.Printf("买入后持仓价为%.3f,持仓%.1f股,买入费用%.3f\n",z/n,n,zz)
	for{
		var c int
		fmt.Println("继续买入选择1，卖出选择2,返回选择3")
		fmt.Scanf("%d\n", &c)
		if c == 1 {
			In(n, z,tuichu)		//递归
			return		//结束此循环
		} else if c == 2 {
			Out(n, z,tuichu)	//递归
			return		//结束此循环
		} else if c == 3{
			*tuichu = false		//退出时更改全局变量
			return		//结束此循环
		} else {
			fmt.Println("输入错误")	//继续循环
		}
	}
}
func Out(n,z float32,tuichu *bool) {
	//卖出时需要的费用
	if *tuichu == false {
		return
	}
	var nnn,mmm,zzz,s float32
	fmt.Println("请输入卖出几手股份(1手=100股)")
	fmt.Scanf("%f\n",&nnn)
	nnn = nnn*100
	if nnn > n{
		fmt.Println("没那么多股份")
		return
	}
	fmt.Println("请输入卖出价格")
	fmt.Scanf("%f\n",&mmm)
	zzz = nnn*mmm
	n = n-nnn
	z = z-zzz
	z = z/n
	s = zzz*0.001
	if zzz*0.0003<=5 {
		s = s+5
		s = zzz*0.00002+s
		fmt.Printf("手续费：%.3f\n",s)
	}else {
		s = zzz*0.0003+s
		s = zzz*0.00002+s
		fmt.Printf("手续费：%.3f\n",s)
	}
	zzz = zzz-s
	if n == 0 {
		z = 0
	}
	//卖出后持仓
	fmt.Printf("卖出后持仓价格为%.3f,卖出价格为%.3f\n",z,zzz)
	for{
		var c int
		fmt.Println("买入选择1，继续卖出选择2,返回选择3")
		fmt.Scanf("%d\n",&c)
		if c == 1 {
			In(n, z,tuichu)
			return
		} else if c == 2 {
			Out(n, z,tuichu)
			return
		} else if c == 3{
			*tuichu = false
			return
		}else {
			fmt.Println("输入错误")
		}
	}
}

func main(){
	for{
		tuichu := true	//定义变量，控制递归退出
		fmt.Println("计算做T、补仓、平仓所需要的手续费")
		var n, m, z float32
		var c int
		fmt.Println("输入拥有几手股份(1手=100股)，还未持仓输入0")
		fmt.Scanf("%f\n", &n)
		if n == 0 {		//如果未持仓直接跳转买入函数
			In(0,0,&tuichu)	//指针传递变量，否则无法更改变量
		}
		fmt.Println("输入现在持有价格")
		fmt.Scanf("%f\n", &m)
		n = n * 100
		z = n * m
		fmt.Printf("目前持有总价为%.3f\n", z)
		fmt.Println("买入选择1，卖出选择2")
		fmt.Scanf("%d\n", &c)
		if c == 1 {
			In(n, z,&tuichu)    //跳转买入函数，指针传递变量，否则无法更改变量
		} else if c == 2 {
			Out(n, z,&tuichu)    //跳转卖出函数，指针传递变量，否则无法更改变量
		} else {
			fmt.Println("输入错误")
		}
	}

}