Answer 1

-----Stack-----

* Stored in computer RAM just like the heap.
* Variables created on the stack will go out of scope and are automatically deallocated.
* Much faster to allocate in comparison to variables on the heap.
* Implemented with an actual stack data structure.
* Stores local data, return addresses, used for parameter passing.
* Can have a stack overflow when too much of the stack is used (mostly from infinite or too deep recursion, very large allocations).
* Data created on the stack can be used without pointers.
* You would use the stack if you know exactly how much data you need to allocate before compile time and it is not too big.
* Usually has a maximum size already determined when your program starts.

-----Heap-----

* Stored in computer RAM just like the stack.
* In C++, variables on the heap must be destroyed manually and never fall out of scope. The data is freed with delete, delete[], or free.
* Slower to allocate in comparison to variables on the stack.
* Used on demand to allocate a block of data for use by the program.
* Can have fragmentation when there are a lot of allocations and deallocations.
* In C++ or C, data created on the heap will be pointed to by pointers and allocated with new or malloc respectively.
* Can have allocation failures if too big of a buffer is requested to be allocated.
* You would use the heap if you don't know exactly how much data you will need at run time or if you need to allocate a lot of data.
* Responsible for memory leaks.

https://stackoverflow.com/questions/79923/what-and-where-are-the-stack-and-heap