package t2;
import java.util.Scanner;
public class test {
    public static void main(String[] args) {
        for(;;)
        {
        Scanner input = new Scanner(System.in);   
        System.out.println("请输入学生的分数：");
        double score = input.nextDouble();
        int level1,level2;
        if(score>=90.0 && score<=100.0){ level1 = 1;}
        else if(score>=80.0){ level1 = 2;}
        else if(score>=70.0){ level1 = 3;}
        else if(score>=60.0){ level1 = 4;}
        else{ level1 = 5;}
            
        if(score>=85.0&&score<=100.0){level2 = 1;}
        else if(score>=70.0){level2 = 2;}
        else if(score>=60.0){level2 = 3;}
        else{level2 = 4;}
        switch(level1)
        {
        case 1:
            System.out.print("该生的成绩等级是：  优");
            break;
        case 2:
            System.out.print("该生的成绩等级是：  良");
            break;
        case 3:
            System.out.print("该生的成绩等级是：  中");
            break;
        case 4:
            System.out.print("该生的成绩等级是： 及格");
            break;
        case 5:
            System.out.print("该生的成绩等级是： 不及格");
            break;
        }  
        switch(level2)
        {
        case 1:
            System.out.println("   A ");
            break;
        case 2:
            System.out.println("   B ");
            break;
        case 3:
            System.out.println("   C ");
            break;
        case 4:
            System.out.println("   D ");
            break;
        }
        }    
}
}

结果：

package t2;
import java.util.Scanner;
public class test {
    public static void main(String[] args) {
        for(;;)
        {
        Scanner input = new Scanner(System.in);   
        System.out.println("请输入学生的分数：");
        double score = input.nextDouble();
        int level1,level2;
        if(score>=90.0 && score<=100.0){ level1 = 1;}
        else if(score>=80.0){ level1 = 2;}
        else if(score>=70.0){ level1 = 3;}
        else if(score>=60.0){ level1 = 4;}
        else{ level1 = 5;}
            
        if(score>=85.0&&score<=100.0){level2 = 1;}
        else if(score>=70.0){level2 = 2;}
        else if(score>=60.0){level2 = 3;}
        else{level2 = 4;}
        switch(level1)
        {
        case 1:
            System.out.print("该生的成绩等级是：  优");
            break;
        case 2:
            System.out.print("该生的成绩等级是：  良");
            break;
        case 3:
            System.out.print("该生的成绩等级是：  中");
            break;
        case 4:
            System.out.print("该生的成绩等级是： 及格");
            break;
        case 5:
            System.out.print("该生的成绩等级是： 不及格");
            break;
        }  
        switch(level2)
        {
        case 1:
            System.out.println("   A ");
            break;
        case 2:
            System.out.println("   B ");
            break;
        case 3:
            System.out.println("   C ");
            break;
        case 4:
            System.out.println("   D ");
            break;
        }
        }    
}
}

结果：