5 二重循环

int classNum = 3;
        int studentNum = 4;
        Scanner scanner = new Scanner(System.in);
//        外层循环控制班级数目
        for(int i = 0; i < classNum; i++)
        {
            int total = 0;//某个班级全部学员的总成绩
            for(int j = 0; j < studentNum; j++)
            {
                System.out.println("请输入第"+(i+1)+"个班级"+"第"+(j+1)+"个学员的成绩");
                int score = scanner.nextInt();
                total += score;
            }
            System.out.println("第"+(i+1)+"个班级的平均成绩是" + total/4);
        }

for(int i = 0; i <classNum; i++){
        sum = 0.0;                      
        System.out.println("请输入第" + (i+1) + "个班级的成绩");
        for(int j = 0; j < score.length; j++){ 
            System.out.print("第" + (j+1) + "个学员的成绩：");
            score[j] = input.nextInt();
            sum = sum + score[j];   
        }
        aver [i] = sum / score.length;          //计算平均分
        System.out.println(“第”+(i+1)+“个班级平均分" + aver [i] + "\n");
    }

for (int m = 0; m < 5; m++)
        {
            for (int i = 0; i < 5; i++)
            {
                System.out.print("*\t");
            }
            System.out.println("");
        }

//*****
//****
//***
//**
//*
//        第1行 m=5,里层循环要打印5个*
//        第2行 m=4,里层循环要打印4个*
//        第3行 m=3,里层循环要打印3个*
        //for (int m = 0; m < 5; m++)//控制的是打印多少行
        Scanner scanner  = new Scanner(System.in);
        System.out.println("输入行数");
        int row = scanner.nextInt();
        for (int m = row; m > 0; m--)//控制的是打印多少行
        {
            for (int i = 0; i < m; i++)//控制的是每行打印多少列
            {
                System.out.print("*\t");
            }
            System.out.println("");
        }

for (int m = 0; m < 9; m++)//控制的是打印多少行
        {
            for (int i = 0; i < 1+m; i++)//控制的是每行打印多少列
            {
                System.out.print((i+1)+"*"+(m+1)+"="+((i+1)*(m+1))+"\t");
            }
            System.out.println("");
        }