creating a queue of pointers in c - c

Question

i have a dynamic number of pointers all having the same size. i need to store all the addresses of my pointers in some place like a link List in order to fetch them later on.
my question is what structs should i use. is the following correct:
struct Node{
int *k;
Node*Next;
}
struct LS{
Node*first,*last;
void push(Node*n);
Node* GetFirst();
Node* GetLast();
}
the LS is the linked list that stores Nodes. and a Node is a struct that holds the address of my pointer and a pointer to the next Node.
am i using int *k to store the address of my pointer correctly? should i continue with this implementation or is there any easier way to do this?

Answer 1

this sample code may help you start...
#include <stdio.h>
struct Node{
int *k;
Node *Next;
}* Temp;
struct LS
{
Node *first,*last;
void push(Node *MyNode)
{
MyNode->Next=NULL;
if(empty())
{
first=MyNode;
last=MyNode;
}
else
{
last->Next = MyNode;
last=MyNode;
}
}
Node* front()
{
return first;
}
void pop()
{
free(first->k);
first=first->Next;
}
bool empty()
{
if(first==NULL) return true;
return false;
}
};
int N=10;
int main()
{
LS Q;Q.first=NULL;
for(int i=0;i<3;i++)
{
Node *NewNode= (Node*)malloc(sizeof(Node));
NewNode->k = (int*)malloc(sizeof(int)*N);
for(int k=0;k<N;k++) NewNode->k[k]=i;
Q.push(NewNode);
}
while(!Q.empty())
{
Temp=Q.front();
for(int i=0;i<N;i++) printf("%d ",Temp->k[i]);
printf("\n");
Q.pop();
}
return 1;
}

Answer 2

Yes, your Node struct is correct.
As to whether there is an easier way it depends. If there is a maximum number of pointers that you will need then an array of pointers would be easier. If you can do it in C++ then an STL vector (can use it like an array, but underneath the hood it can grow dynamically as needed) is easier. If you have to do it in C and it has to be dynamic, though, then no, there is not an easier way.

Answer 3

WDM.H (microsoft header) has a bunch of linked list stuff to look at ( http://msdn.microsoft.com/en-us/library/ff547799(VS.85).aspx ) , I've cut and pasted from that, and added a very simple example.
typedef struct _LIST_ENTRY {
struct _LIST_ENTRY *Flink;
struct _LIST_ENTRY *Blink;
} LIST_ENTRY, *PLIST_ENTRY;
typedef struct _MY_THING
{
LIST_ENTRY ListEntry;
ULONG randomdata1;
ULONG randomdata2;
ULONG randomdata3;
ULONG randomdata4;
} MY_THING, *PMY_THING;
#define CONTAINING_RECORD(address, type, field) ((type *)( \
(PCHAR)(address) - \
(ULONG_PTR)(&((type *)0)->field)))
VOID
InsertHeadList(
IN PLIST_ENTRY ListHead,
IN PLIST_ENTRY Entry
)
{
PLIST_ENTRY Flink;
Flink = ListHead->Flink;
Entry->Flink = Flink;
Entry->Blink = ListHead;
Flink->Blink = Entry;
ListHead->Flink = Entry;
}
VOID
InitializeListHead(
IN PLIST_ENTRY ListHead
)
{
ListHead->Flink = ListHead->Blink = ListHead;
}
PLIST_ENTRY
RemoveHeadList(
IN PLIST_ENTRY ListHead
)
{
PLIST_ENTRY Flink;
PLIST_ENTRY Entry;
Entry = ListHead->Flink;
Flink = Entry->Flink;
ListHead->Flink = Flink;
Flink->Blink = ListHead;
return Entry;
}
void main()
{
LIST_ENTRY HeadOfMyList;
MY_THING Thing;
InitializeListHead(&Head);
// example of add thing to list.
InsertHeadList(&HeadOfMyList, &Thing.ListEntry);
// example of removing thing from the list
PLIST_ENTRY listEntry = RemoveHeadList(&HeadOfMyList);
PMY_THING pThing = (PMY_THING) CONTAINING_RECORD(listEntry, MY_THING, ListEntry);
}