java入门------else...if------成绩查询小程序

import java.util.Scanner;
public class Demo {
	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		System.out.println("请输入成绩：");
		double score=scan.nextDouble();
		if(score>=0&&score<60){
			System.out.println("成绩为差");
		}else if(score>=60&&score<80){
			System.out.println("成绩中等");
		}else if(score>=80&&score<90){
			System.out.println("成绩为良");
		}else if(score>=90&&score<=100){
			System.out.println("成绩优秀");
		}else {
			System.out.println("成绩输入错误，请重新运行！");
		}		
	}
}

import java.util.Scanner;
public class Demo1 {
	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		System.out.println("请输入成绩：");
		int score=scan.nextInt();
		if(score>=90){
			System.out.println("优");
		}else if(score>=80){
			System.out.println("良");
		}else if(score>=60){
			System.out.println("中");
		}else if(score>=0){
			System.out.println("差");
		}
	}
}