Dynamically store lines of strings using C

Question

I want to store lines of strings dynamically using C language.

for e.g

sadasdasda5245sdf

fadfa6456

fasdf90-70=790

the number of such lines and the length of each line can be anything.Is there any way to store the whole thing dynamically.

Answer 1

There are several data structures that allow you to add items dynamically, without having to know in advance what the maximum number of elements required are. There are linked lists, binary search trees, balanced trees, tries, heaps and many more.

Similarly, there are lots of ways of dynamically allocating strings of different lengths.

The easiest way would probably be to use a simple linked list:

typedef struct _node {
    struct _node *next;
    char *value;
} node_t;

You keep track of the head, the first item in the list, and each next field points to the next node in the list. For example, to traverse the list, you would write something like this:

currentNode = head;
while(currentNode != NULL) {
    /* do something with currentNode->value */
    currentNode = currentNode->next;
}

Without knowing what you want to do, specifically, I can't really offer any better suggestions.

What operations do you want to carry out on your data structure often? Are you going to simply be iterating through the strings, searching for strings, adding and removing strings?

Answer 2

There are several data structures that allow you to grow dynamically. As the 2 previous replies suggest, you can use an array of pointers, a linked-list etc.

It all depends on the requirements of your implementation:

1. Will you be accessing those strings more than once?
2. Once you obtain them, do you intend to access them all (for some calculation) or one at a time (i.e. a dictionary)?
3. What are your space/memory consideration?
4. Is there any importance to the order in which you get them (suggesting a queue or a stack implementation)?
5. Is there an inherent connection between the strings (suggesting a tree or tree-like structure)?

etc. I suggest reading a bit about data structures and deciding what suits you best. They can all be implemented in C.
Look at this Wikipedia article (go to the 'Examples' section for a list of options, if you want to skip the theory)