程序代码：

class Point{
      public int sum(int x, int y , int z ){
            sum =x + y + z;
            return sum;
          }
      public int aver(int x , int y , int z){
        aver = (x + y + z)/3;
        return aver;         
           }
           public static void main (String args []){
               Point num = new num();
               System.out.println(num.sum(90,90,90));
               System.out.println(num.aver(90,90,90));
               System.out.println("这个就是同学的成绩"）；
               }
     
    }