go經典練習題涉及流程控制-字符串-struct-map的數據類型的處理

one：求1到100之間的質數

package main

import (
	"fmt"
)

func isPrime(n int) bool {
	var flag = true
	for j := 2; j < n; j++ {
		if n % j == 0 { //計算質數，若是這個數能被本身整除哪麼它就是質數
			flag = false
			break
		}
	}
	return flag
}

func main() {
	var n int = 100
	for i := 2; i < n; i++ {
		if isPrime(i) {
			fmt.Printf("%d is prime\n", i)
		}
	}
}

　　

two:統計字符串中有哪些單詞並統計出出現次數

package main

import (
	"fmt"
)

func addWord(wordCount map[string]int, chars []rune) {
	words := string(chars)
	if len(words) > 0 {
		count, ok := wordCount[words]
		if !ok {
			wordCount[words] = 1

		} else {
			wordCount[words] = count + 1
			
		}
	}	
}

func main() {
	str := "how are hou! you are welcome!"
	var tmp []rune
	var wordCount map[string]int = make(map[string]int, 10)
	var chars []rune = []rune(str)
	for i := 0; i < len(str); i++ {
        if str[i] >= 'a' && str[i] <= 'z'|| str[i] >= 'A' && str[i] <= 'Z' {
			tmp = append(tmp, chars[i])
		} else {
			addWord(wordCount, tmp)
			tmp = tmp[0:0]
		}
	}
	if len(tmp) > 0 {
		addWord(wordCount, tmp)
	}
	for k,v := range wordCount {
		fmt.Printf("key:%s v:%d\n", k, v)	
	}
}

Three:統計字符串中每個字符個數

package main

import (
	"fmt"
)

func addWord(charCount map[rune]int, char rune) {

 		count, ok := charCount[char]
		if !ok {
			charCount[char] = 1

		} else {
			charCount[char] = count + 1
			
		}
	
}

func main() {
	str := "how are hou! you are welcome!中國"
	var charCount map[rune]int = make(map[rune]int, 10)
	var chars []rune = []rune(str)
	for i := 0; i < len(chars); i++ {
			addWord(charCount, chars[i])
	}
	for k,v := range charCount {
		fmt.Printf("key:%c v:%d\n", k, v)	
	}
}

　　

Four:簡易版學生信息管理系統

package main

import (
	"os"
	"fmt"
)

type Student struct {
	Id string
	Name string 
	Age int
	Sex string
	Score float32
}

func showMenu() {
	fmt.Printf("please select:\n")
	fmt.Printf("1.添加學生信息\n")
	fmt.Printf("2.修改學生信息\n")
	fmt.Printf("3.顯示學生列表\n")
	fmt.Printf("4.退出\n")

}

func getStudentInfo() Student {
	var stu Student
	fmt.Printf("Please input Id:\n")
	fmt.Scanf("%s\n",&stu.Id)
	
	fmt.Printf("Please input name:\n")
	fmt.Scanf("%s\n",&stu.Name)

	fmt.Printf("Please input Age:\n")
	fmt.Scanf("%d\n",&stu.Age)

	fmt.Printf("Please input Sex:\n")
	fmt.Scanf("%s\n",&stu.Sex)

	fmt.Printf("Please input Score:\n")
	fmt.Scanf("%f\n",&stu.Score)
	return stu
}

func addStudent(allStudent map[string]Student) {
	stu  := getStudentInfo()
	_, ok := allStudent[stu.Id]
	if ok {
		fmt.Printf("studnet %s is exists\n",stu.Id)
		return 
	}
    allStudent[stu.Id] = stu
}

func modifyStudent(allStudent map[string]Student) {
	stu  := getStudentInfo()
	_, ok := allStudent[stu.Id]
	if !ok {
		fmt.Printf("studnet %s is not exists\n",stu.Id)
		return 
	}
    allStudent[stu.Id] = stu
}

func showStudnetList(allStudent map[string]Student) {
    for _, val := range allStudent {
		fmt.Printf("Id:%s\nName:%s\nAge:%d\nSex:%s\nScore:%f\n", val.Id, val.Name, val.Age, val.Sex, val.Score)

	}
}
func main() {
	var sallStudent map[string]Student = make(map[string]Student, 10)
	for {
		showMenu()
		var sel int
		fmt.Println("-------------------------")
		fmt.Scanf("%d\n", &sel)
		switch sel {
		case 1:
			addStudent(sallStudent)
		case 2:
		case 3:
			showStudnetList(sallStudent)
		case 4:
            os.Exit(0)
		}
	}
}