Thread: functions which change arrays without pointers?

the book I learn from gave a task to write a program which gets a matrix , and we have to write a function that switches 2 columns or rows the user inputs .
this chapter still not covers the pointers subject . as far as I know a function can not change variables in the main function without using pointers .
so , theoretically, can a function described here can be written without using pointers ? as far as I tried - it can not . am I missing something here or the book's just wrong?

thank you!