Storage Allocation

The different ways to allocate memory are:

1. Static storage allocation
2. Stack storage allocation
3. Heap storage allocation

Static storage allocation

• In static allocation, names are bound to storage locations.
• If memory is created at compile time then the memory will be created in static area and only once.
• Static allocation supports the dynamic data structure that means memory is created only at compile time and deallocated after program completion.
• The drawback with static storage allocation is that the size and position of data objects should be known at compile time.
• Another drawback is restriction of the recursion procedure.

Stack Storage Allocation

• In static storage allocation, storage is organized as a stack.
• An activation record is pushed into the stack when activation begins and it is popped when the activation end.
• Activation record contains the locals so that they are bound to fresh storage in each activation record. The value of locals is deleted when the activation ends.
• It works on the basis of last-in-first-out (LIFO) and this allocation supports the recursion process.

Heap Storage Allocation

• Heap allocation is the most flexible allocation scheme.
• Allocation and deallocation of memory can be done at any time and at any place depending upon the user's requirement.
• Heap allocation is used to allocate memory to the variables dynamically and when the variables are no more used then claim it back.
• Heap storage allocation supports the recursion process.

Example:

1. fact (int n)  
2. {  
3.    if (n<=1)  
4.        return 1;  
5.    else   
6.        return (n * fact(n-1));  
7. }  
8. fact (6)  

The dynamic allocation is as follows: