Even still, no.
I thought, that he as a beginner should just allocate all of them on the heap, so that he doesn't get problems like for example stack overflows. I simply should've said that
Stack overflow is a rare problem, mostly caused by excessive recursion or placing large arrays on the stack (or objects that contain large arrays). It is also generally easy to fix.
Allocating data on the heap can lead to lots of common problems, including memory leaks and bad pointers. These problems can be difficult to track down and fix. It also is a bad idea to do dynamic allocation when it is unnecessary from a performance standpoint, because each allocation/deallocation involves traversing some data structure. Stack allocation is virtually free in comparison.