public class 成绩的等级
{
public static void main(String[] args)
{
java.util.Scanner s = new java.util.Scanner(System.in);
System.out.print("请输入您的考试成绩：" );
double i = s.nextDouble();
if(i < 0 || i > 100)
System.out.print("对不起，您输入的成绩不合法" );
else if(i < 60)
System.out.println("不及格");
else if(i < 70)
System.out.println("及格");
else if(i < 80)
System.out.println("中");
else if(i < 90)
System.out.println("良");
else if(i <= 100)
System.out.println("优");
}
}