public class Main {

    public static void main(String[] args) {

        // 用二维数组表示的学生成绩:

        int[][] scores = {

                { 82, 90, 91 },

                { 68, 72, 64 },

                { 95, 91, 89 },

                { 67, 52, 60 },

                { 79, 81, 85 },

        };

        // TODO:

        double average = 0;

        double sum=0.0,num=0.0;

        for(int i=0;i<scores.length;i++)

        {

         int [] arr=scores[i];

         num+=arr.length;

         for(int j=0;j<arr.length;j++)

          sum+=arr[j];

        }

        average=sum/num;

    if (Math.abs(average - 77.733333) < 0.000001) {

        System.out.println("测试成功");

    } else {

        System.out.println("测试失败");

    }

}

}