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POwarning incompatible pointer, why this happens?
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copied!<pre><code>#include <stdio.h> typedef int element_type; typedef struct Cell{ element_type e; struct Cell *next; } Cell,*List; Cell *End(List L){ Cell *q = L; while (q->next != NULL){ q = q->next; } return q; } void Insert(Cell *p, element_type x){ //Create new Cell Cell *temp = (Cell*) malloc(sizeof(Cell)); if (temp == NULL){ printf("Memory Allocation Failed"); } else{ temp->e = x; temp->next = p->next; p->next = temp; } } element_type Retrieve(Cell *p){ return p->e; } int main(){ //Initialize the List; List L = malloc(sizeof(Cell)); L->e = NULL; L->next = NULL; element_type x = 10; Insert(L,x); printf("Just retrievd the item %d\n",Retrieve(L)); return 1; } List_pointer.c: In function ‘Insert’: List_pointer.c:19:24: warning: incompatible implicit declaration of built-in function ‘malloc’ [enabled by default] List_pointer.c: In function ‘main’: List_pointer.c:35:12: warning: incompatible implicit declaration of built-in function ‘malloc’ [enabled by default] List_pointer.c:36:8: warning: assignment makes integer from pointer without a cast [enabled by default] </code></pre> <p>Thanks for all your helps, and I for the part with struct now. However, when I tried to use malloc, I got the warnings again on incompatible declaration. I thought malloc returns a generic pointer to NULL, and hence there shouldn't be any issue with casting? I just not sure what I did wrong here. </p> <p>Also for those of you who wonders why I would implement such a weird interface, I was following the interfaces provided by the book "Data Structure and Algorithm" by Aho. The sample codes were given in Pascal, pretty old style. Although I think there are some merits to learn this super old style way of designing data structure.</p> <p><strong>Update:</strong></p> <p>I just forgot to include the stdlib.h header for malloc! Please refer to this link <a href="https://stackoverflow.com/questions/7050798/incompatible-implicit-declaration-of-built-in-function-malloc">incompatible implicit declaration of built-in function ‘malloc’</a></p>

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