Работа со стеком - С(Си)

#include <stdio.h>
#include <stdlib.h>
 
 
struct stack
{
struct listnode *top;
int size;
};
 
struct listnode {
char *data; /* Data */
int value; /* Data */
struct listnode *next; /* Next node */
};
 
struct stack *stack_create()
{
struct stack *s = malloc(sizeof(*s));
if (s != NULL) {
s->size = 0;
s->top = NULL;
}
return s;
}
 
int stack_size(struct stack *s)
{
return s->size;
}
 
struct listnode *list_addfront(
struct listnode *list,
char *data, int value)
{
struct listnode *newnode;
newnode = list_createnode(data, value);
if (newnode != NULL) {
newnode->next = list;
return newnode;
}
return list;
}
 
 
int stack_push(struct stack *s, int value)
{
s->top = list_addfront(s->top, value); /*Здесь пишет ошибку [Warning] assignment makes pointer from integer without a cast*/
if (s->top == NULL) {
fprintf(stderr,
"stack: Stack overflow\n");
return -1;
}
s->size++;
return 0;
}
 
int stack_pop(struct stack *s)
{
struct listnode *next;
int value;
if (s->top == NULL) {
fprintf(stderr, "stack: Stack underflow\n");
return -1;
}
next = s->top->next;
value = s->top->value;
free(s->top);
s->top = next;
s->size--;
return value;
}
 
int main()
{
struct stack *s;
int i, val;
s = stack_create();
for (i = 1; i <= 10; i++) {
stack_push(s, i);
}
for (i = 1; i <= 11; i++) {
val = stack_pop(s);
printf("pop: %d\n", val);
}
return 0;
}