Fácil sistema de clasificación del estudiante

/*
 * 需求：
 *     考试成绩等级系统;
 *     [90-100]    A
 *     [80-90)     B
 *     [70-80)     C
 *     [60-70)     D
 *     (0-60)      E*/
public class Grade {

	public static void main(String[] args) {
		java.util.Scanner s = new java.util.Scanner(System.in);
		System.out.print("请输入考生成绩：");
		double score = s.nextDouble();
		int grade = (int)(score/10);
		
		if(score < 0 || score > 100) {
			System.out.println("您输入的考生成绩不正确！");
		}else {
		switch(grade) {
		case 9: case 10:
			System.out.println("成绩等级为：A");
			break;
		case 8: 
			System.out.println("成绩等级为：B");
			break;
		case 7: 
			System.out.println("成绩等级为：C");
			break;
		case 6: 
			System.out.println("成绩等级为：D");
			break;
		case 5: 
			System.out.println("成绩等级为：E");
			break;
		case 4: 
			System.out.println("成绩等级为：E");
			break;
		case 3: 
			System.out.println("成绩等级为：E");
			break;
		case 2: 
			System.out.println("成绩等级为：E");
			break;
		case 1: 
			System.out.println("成绩等级为：E");
			break;
		case 0: 
			System.out.println("成绩等级为：E");
			break;
		
		}
		}
		

	}

}