Storage Management

Rudimentary storage allocator using the Stack data structure. Section 5.4 of The C Programming Language.

About the project:

alloc(n) returns a pointer p to n consecutive character positions which can be used by the caller of alloc for storing characters.
afree(p) releases the storage thus acquired so it can be reused later.
The routines are "redimentary" because the calls to afree must be made in the opposite order to the calls made on alloc.
The storage managed by alloc and afree is a Stack.

How `allocbuf` is used:

We use a pointer called allocp that points to the next free element.
When alloc is asked for n characters, it checks to see if there is enough room left in allocbuf. If so, alloc returns the currect value of allocp (the beginning of the free block), then increments it by n to point to the next free area.
If there is no room, alloc returns zero.
afree(p) merely sets allocp to p if p if inside allocbuf.

What did I learn from this:

Arrays with pointers in C.
Pointer arithmetics and comparison.