输入成绩进行判断，然后输出ABCDE

需求：输入分数进行成绩判断，输出ABCDEF。

package Chengji;
import java.util.Scanner;

public class Chengjipanduan {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		boolean flag = true; 
		System.out.println("请输入你的成绩：");
		int score = scan.nextInt(); 
		char c = ' '; 
		do {
			if (90 <= score && score <= 100) {
				c = 'A';
				break;
			} else if (80 <= score && score < 90) {
				c = 'B';
				break;
			} else if (70 <= score && score < 80) {
				c = 'C';
				break;
			} else if (60 <= score && score < 70) {
				c = 'D';
				break;
			} else if (0 < score && score < 60) {
				c = 'E';
				break;
			} else {
				flag = false;
				System.out.println("输入有误，请重新输入：(0-100之间)");
				score = scan.nextInt();
			}
		} while (!flag);
		System.out.println("你的成绩为：" + c);
	}
}