Question

As mentioned in this tutorial:
http://www.learncpp.com/cpp-tutorial/79-the-stack-and-the-heap/

In computer programming, a stack is a container that holds other
variables (much like an array). However, whereas an array lets you
access and modify elements in any order you wish, a stack is more
limited. The operations that can be performed on a stack are identical
to the ones above:

1) Look at the top item on the stack (usually done via a function
called top()) 2) Take the top item off of the stack (done via a
function called pop()) 3) Put a new item on top of the stack (done via
a function called push())

But if I defined two variables in C++ I do not have to use them in the same order of definition:

Example:

int main() {
 int a;
 int b;

 b = 5;
 a = 6;
}

Is there a problem on this code? I can use them in any order I like!! I do not have to use the a first then the b.

Am I misunderstanding something? What is it?

Answer 1

You are confusing two different kinds of stacks.

One stack, is where some of the memory for your application is allocated. This would be part of a discussion about the stack and heap and where your memory is allocated.

The other kind of stack is a data structure that conforms to a LIFO style of access. This could be implemented using a std::vector or other forms of data structures.