Memory management in depth. Lets discuss stacks and heaps

Memory management is process of controlling, allocating and using computer memory to optimize overall performance of system. Now this may sound a bit foggy but don't worry we will discuss it one by one.

Each time a program runs on your computer, a memory block is allocated to it by your Operating System. We call this memory block a segment. Each segment is then further divided into smaller blocks which is used to store chunks of data. Below visual representation of memory segment

Well that's where addresses comes in. In your memory segment, each block has a separate and unique address. Computer uses that address to read/write/update value stored in that block. Each time a variable is declared in your program, computer assigns a memory block to it in stack or heap depending upon the request made by user. BUT what is this stack and heap? Lets find out together.

Stack vs Heap

Remember memory segment? Well turns out that your memory segment is divided into three main parts

Stack

Heap

Code Block

Now lets go a bit deeper and discuss these thing more technically. Lets just say you declare a function call myFunc. And you have declared some variables in it such as int a,b. So your function will look something like this.

After you declare your function like this, this is how your memory segment look

Here's how you can initialize a pointer

BUT there is a catch. In stacks memory is deallocated automatically after we go out of scope of variable but that is not the case in heap. Heap memory should be deallocated explicitly. And that is where the keyword delete comes in.

Here's how its done

What it will do is delete everything stored on address in ptr. And assign NULL to ptr.