Why you use linked list instead of arrays?

Answer 1

You would use linked lists instead of arrays in two instances:

1) You don't know how long your list will be and it is apt to dramatically change length.

2) You will make lots of additions and removals in the middle of your list.

Answer 2

A "linked list" uses pointers to refer to the next and/or previous members in a list. A single-linked list uses only one pointer to refer, typically, to the next member, whereas a doubly-linked list uses two pointers to refer to the next and previous members.

Linked lists are useful if you intend to remove or add items from anywhere in the list: beginning, middle or end. In an array, you'd have to shift entire sections of memory around if you wanted to add or remove items. In a linked list, however, you merely change a couple of pointers and allocate or free memory for an item.

By its very nature, a stack is a LIFO (Last In First Out) structure. A computer processor uses stacks, for instance, to push items onto and pop items off of the end of a list. The term "stack" means that items other than that on the end of the list is not available for use under any circumstances. You can only push an item onto the end of a stack, and pop an item off from the end of the stack.

Linked lists are considered an inappropriate methodology for implementing stacks primarily because you end up using more computer memory for storing a linked list than you would an array. It's recommended you stick to arrays using the realloc() style of functions, since the processor and memory usage are, in comparison to the respective usages of linked lists, minimal.