C++: What is the difference between stack and heap?

Stack — automatic, fast, limited. Heap — manual, slow, large.

1void func() {
2    int x = 10;        // Stack
3    int* p = new int;  // Heap
4}

Stack:

• Automatic cleanup.
• ~1-8 MB.
• Very fast.

Heap:

• Manual cleanup.
• GB available.
• Slower.