Advanced C Programming: Pointers

The address of the array is the same as the address of the first item in the array. Why is that important?

How can pointer values be displayed?

Let’s see how pointers and addresses work – and why arrays are special.

Pointers to pointers

Pointers to pointers to integers

Arrays of arrays of characters

What is **argv in the main() function?

Pointers to void

Setting aside storage space

How to allocate the right amount of memory for a specific amount of data

Why does your C compiler will complain about some functions?

How to clear memory before allocating

How to free memory that is no longer needed 

How to change the size of a block of allocated memory

What does it mean when you add 1 to a pointer?

Using pointer arithmetic with arrays

But how much memory does a struct need?

Why the order of fields in a struct is important

Understanding that data types of a certain size are aligned on boundaries of that size

Pointer arithmetic works with complex types as well as simple types

Still confused by pointers? Here I show how to use your debugger to understand indirection

Here’s another example of how to use a debugger with multiple indirection – pointers to pointers to pointers, and see how they are stored in memory

This document contains some brief notes on topics covered in Step Two of the course. You may want to refer to use these notes as a revision aid or to help clarify important points from this section. 

Limitations of arrays and using linked lists as an alternative

How is a linked list different from an array?

Lists that include one pointer linking each element to the next one

Do you really always need to free memory?

Lists whose elements contain pointers to each adjacent element

An example showing how to create a simple double-linked list

Initializing a doubly-linked list not quite as simple as initializing a singly-linked list

A sample project showing a doubly-linked list

Queues are very common data structures in programming – here I explain what they are

Using a doubly linked list as a queue

A stack is another important type of data structure – here we see how it differs from a queue

You may need pointers with a stack, but you may not need a linked list

Adding and removing items to and from a stack

Iterating over list elements

Making a new copy of an existing queue

How would you delete an item from the middle of a list?

How would you add an item into a list?

What is a function pointer and what are they for?

The strange syntax for declaring a function pointer

How a single piece of code can call different functions using function pointers

This document contains some brief notes on topics covered in Step Three of the course. You may want to refer to use these notes as a revision aid or to help clarify important points from this section. 

Pointers are one of the major sources of error in C programs. But why?

When is a copy not a copy?

Sometimes a copy may not be what you think it is!

Allocating the wrong amount of memory is a recipe for disaster

When you cast a pointer you are not really changing anything. But an incorrect cast can cause problems even so

An example of a cast that didn’t work as expected

What happens if you free some memory twice?

When memory is allocated but not freed

What happens when you try to use memory that has already been freed?

Trying to access things that can’t be accessed

What happens if you use a pointer that doesn’t point to anything?

This document contains some brief notes on topics covered in Step Four of the course. You may want to refer to use these notes as a revision aid or to help clarify important points from this section. 

That’s it! So where to next? Here are a few pointers…