错在何处
import java.util.*;
public class Grade{
public static void main(String args[]){
Scanner in=new Scanner(System.in);
System.out.println("请输入等级：");
String grade=in.nextLine();
switch(grade){
case"A":System.out.println(grade+"is 85~100");
break;
case"B":System.out.println(grade+"is 70~84");
break;
case"C":System.out.println(grade+"is 60~69");
break;
case"D":System.out.println(grade+"is<60") ;
break;
default:System.out.println("input error");
}
}
}
错在何处。。

[解决办法]
case"A" jdk1.7貌似才支持String可以修改case 'A'
[解决办法]
貌似没错
[解决办法]

Java code

import java.util.*;public class Grade {    public static void main(String args[]) {        Scanner in = new Scanner(System.in);        System.out.println("请输入等级：");        String grade = in.nextLine();        switch (grade.charAt(0)) {        case 'A':            System.out.println(grade + "is 85~100");            break;        case 'B':            System.out.println(grade + "is 70~84");            break;        case 'C':            System.out.println(grade + "is 60~69");            break;        case 'D':            System.out.println(grade + "is<60");            break;        default:            System.out.println("input error");        }    }}