The heap and the stack are the two places where programs store data (okay,
there are a few more, but they're the two most common ones).
The heap is just a big chunk of memory that is managed by a heap manager (or
garbage collector, in C#'s case). When you write something like:
Employee e = new Employee();
(assuming Employee is a class), you get a chunk of memory allocated out of
the heap to store the information for that employee instance. This instance
will be preserved until it isn't needed anymore (in C#), or until it is
explicitly deleted (in languages like C++).
The stack is used to hold local variables. So, when I write something like:
int i = 15;
as part of a method, that sets aside a chunk of space on the stack to hold
the value "15". When I enter a method, that space is used on the stack, and
when I leave the method, that space is reclaimed for later use.
To be strictly true, in my first example, I not only allocated an instance
of Employee on the heap, I allocated a reference to that on the stack.
Or, to be shorter, all local variables use up space on the stack. If they
are value types, this space is used to store the actual value. If they are
references types, this space is used as a reference (aka pointer) to the
actual value, which is stored on the heap.
Hope that helps.
--
Eric Gunnerson
Visit the C# product team at
http://www.csharp.net
Eric's blog is at
http://blogs.gotdotnet.com/ericgu/
This posting is provided "AS IS" with no warranties, and confers no rights.
