java控制语句

import java.util.*;

public class ForXunhuan {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int a = 0;
while (true) {
System.out.println("请正确输入成绩：0~100");
a = input.nextInt();
if(a>=0&&a<=100)
break;
}
if (a < 100 && a >= 90) {
System.out.println("优秀");

} else if (a > 80) {
System.out.println("良");
} else if (a > 70) {
System.out.println("中");
} else if (a > 60) {
System.out.println("差");
} else {
System.out.println("不及格");
}
}

}

import java.util.*;

public class Sxuhuan {
public static void main(String[] args) {
int a;
int b;
Scanner input = new Scanner(System.in);
while (true) {
System.out.println("请正确输入成绩：0~100");
a=input.nextInt();
if(a>=0&&a<101)
break;
}
b=a/10;
switch(b){
case 10:
case 9:
System.out.println("优秀");
break;
case 8:
System.out.println("良");
break;
case 7:
System.out.println("中");
break;
case 6:
System.out.println("差");
break;
default:
System.out.println("不及格");
break;
}
}
}