Question

i want to know about structure function in c programming

Answer 1

it's used to define ur own data type.............like it's a boz or collection of different datatypes.....

Answer 2

http://www.cprogramming.com/tutorial/c/lesson7.html

Answer 3

i did not had a chance to study it ...... but i had some tutorial videos that they can help u... maybe u can give me ur email i will send them...

Answer 4

The struct keyword tells the compiler to bundle together a bunch of different data into one object, and as A.Avinash_Goutham mentioned, it's mainly used to define new types.

For example, let's say one needs to program a singly-linked list in C. By default, C doesn't have any primitives to provide linked lists (in constrast to languages like Lisp), nor does C's standard library (in contrast to languages like C++ or Java that provide a bunch of general collection types). With C structs, you can implement singly-linked lists yourself :)

One can start by defining the individual nodes of the singly-linked list. Without getting too much into the syntax details to accomplish this in C:

struct node
/* Node for singly-linked lists. */
{
int datum;
struct node *next;
};

In the above struct definition you have a `node' object that contains two fields: a field to put data (of type int) in and another field that contains a `next' pointer to a node object.

Might want to go further and specify lists themselves:

struct list
/* Singly-linked list. */
{
struct node *head;
struct node *tail;
size_t len;
};

You can define functions to allocate or initialize those structs for you:

struct node *new_node(int datum, struct node *next)
{
struct node *node = malloc(sizeof(*node));
if (node != NULL)
{
node->datum = datum;
node->next = next;
}
return node;
}

void free_node(struct node *node)
{
free(node);
}

You can also define functions to perform operations on your structs:

void append_node(struct list *list, struct node *node)
/**
Add a node to the end of a singly-linked list.

Probably better to define insert and delete instead but I'm just making an example :D
*/
{
list->tail->next = node;
}

//Now you can do this:

struct list *new_list(size_t len, int init)
/**
Initialize a singly-linked list with `len' nodes, each initialized to `init', and
return a pointer to the list.
*/
{
struct list *list = malloc(sizeof(*list));
if (list != NULL)
{
if (len == 0)
{
list->head = NULL;
list->tail = NULL;
}
else
{
int i;
list->head = new_node(init,NULL);
list->tail = list->head;
for (i = 1; i < len; ++i)
{
append_node(list, new_node(init, NULL));
}
}
list->len = len;
}
return list;
}

Things just go downhill after this point. :D As you can see, C structs help us define our own data structures. Though C structs aren't as powerful as the Classes and Objects you see in other languages (by comparison, C structs are just dumb data structures with no embedded logic), they get the job of grouping together variables related to particular objects quite well. Imagine implementing a linked list in C (or any data structure apart from array and list) without the use of structs!

Answer 5

looks pretty much like a c++ struct

struct structname
{
type datatypename;
//..
//etc.. as many other data members as you like can be of an type, even classes

}; //DO NOT forget the semicolon

defining a struct in your program// NOTE: must declare the struct before you use it

strucname struct_instance;

//assigning values

struct_instance.datatypename=//whatever appropriate value, don't try to assign a string to an int...

//getting values out

x= struct_instance.datatype

also note struct stores values in the order they are declared... so you can assign a pointer to a struct and read off values as any type by using a void pointer and then converting it to t type pointer...