go student mgr 增删改查管理 fmt.Scanf运用

package main

import (
	"fmt"
	"os"
	//"MyProject/pingguoxueyuan/gostudy/listen13/homework/student_mgr"
)


  // 把下面这个结构体和函数注释了就不能单独go run 运行了,要go build才能把2个文件编译到一起
type Student struct{
	Username string
	Sex int
	Score float32
	Grade string
}


func NewStudent(username string, sex int, score float32,grade string) (stu *Student){
	stu = &Student{
		Username :username,
		Sex:sex,
		Score:score,
		Grade:grade,
	}
	return
}

var (
	AllStudents []*Student
)

func showMenu() {
	fmt.Println("请输入对应的选项号")
	fmt.Println("1. add student")
	fmt.Println("2. modify student")
	fmt.Println("3. ashow all student")
	fmt.Println("4. exited\n")
}


func inputStudent() *Student {
	var (
		username string
		sex int
		grade string
		score float32		
	)
	fmt.Println("Please input username")
	fmt.Scanf("%s \r\n",&username)

	fmt.Println("Please input sex:[0|1]")
	fmt.Scanf("%d \r\n",&sex)

	fmt.Println("Please input grade:[0-6]")
	fmt.Scanf("%s \r\n",&grade)

	fmt.Println("Please input score:[0-100]")
	fmt.Scanf("%f \r\n",&score)

	stu := NewStudent(username,sex,score,grade)	
	return stu
}

func AddStudent()  {
	stu := inputStudent()
	for index,v := range AllStudents {
		fmt.Printf("v.Username == stu.Username is %t\n",v.Username == stu.Username)
		if v.Username == stu.Username{
			fmt.Printf("v.Username =%s,index=%d\n",v.Username,index)
			AllStudents[index] = stu
			return 
		}
	}
	AllStudents  = append(AllStudents,stu)
	fmt.Printf("user %s success inserted\n",stu.Username)
}



func ModifyStudent()  {
	stu := inputStudent()
	for index,v := range AllStudents{
		if v.Username == stu.Username{
			AllStudents[index] = stu
			return 
		}
	}
	fmt.Printf("user %s is not fouond\n", stu.Username)
}



func ShowAllStudent()  {	
	for _,v :=range AllStudents{
		fmt.Printf("user:%s info %#v\n",v.Username,v) 
		}
	}
	


func main() {
	for {
		showMenu()
		var sel int
		fmt.Scanf("%d\n",&sel)  // Scanf 一定要有换行符,否则会把下次的输入的enter换行符读出来

		switch sel{
		case 1:
			AddStudent()
		case 2:
			ModifyStudent()
		case 3:
			ShowAllStudent()
		case 4:
			os.Exit(0)
		}
	}
}