Are there fixed memory allocated for Stack and Heap? -

i understand fact stack grows upwards , heap grows downwards or vice-versa (architecture dependent). but, couldn't find details how it's implemented, doubt is, every process memory block allocated, there restriction on, how max chunk can used stack or heap? or there no restrictions till whole allocated memory consumed?

yes, processes have predetermined stack sizes. have ever tried recurse method/function much? stackoverflow exception. doesn't mean you've went through entire computer's memory. os controls distribution of stack , heap memory each process.