We want to obtain the average of g groups that are in the same school year; being that each group can have n students that each student can take m subjects and that in all subjects three marks are...

We want to obtain the average of g groups that are in the same school year; being that each group can have n students that each student can take m subjects and that in all subjects three marks are averaged to obtain the average of the subject. Write a program in c++ to display the average of the groups, the average of each group and the average of each student.

Do not use arrays.