C++ How to Program, 10/e

... the called function’s non-static local variables need to “go away.” The called function’s stack frame is a perfect place to reserve the memory for the called function’s non-static local variables. That stack frame exists as long as the called function is active. When that function returns—and no longer needs its non-static local variables—its stack frame is popped from the stack, and those non-static local variables no longer exist.

Stack Overflow

Of course, the amount of memory in a computer is finite, so only a certain amount of memory can be used to store activation records on the function-call stack. If more function calls occur than can have their activation records stored on the function-call stack, a fatal error known as stack overflow ...