Procedure signature void sort(int *a, int size) without any pointers is void sort(int a, int size) You can do the rest by yourself by copy/pasting the code to the editor which will tell you about syntax errors.
Procedure void swap(int a, int b) simply swaps the values of a and b. That's easy to write.
Bubble-sort algorithm works fine with a few items in an array. If you have large arrays (+100 items) consider using quick-sort algorithm instead.
.NET has also built-in Array.Sort() method which I would use myself.