stack_linkedlist.c

#include <stdio.h>
#include <malloc.h>

struct node {
  int data;
  struct node *link;
};

typedef struct node stack;

stack *getnode()
{
  stack *tmp;
  tmp = (stack *)malloc(sizeof(stack));
  tmp->link = NULL:
  return tmp;
}

void push(stack **top, int data)
{
  stack *tmp;
  tmp = *top;
  *top = getnode();
  (*top)->data = data;
  (*top)->link = tmp;
}

int pop(stack **top)
{
  stack *tmp;
  int num;
  tmp = *top;
  if(tmp == NULL) {
    printf("stack is empty!\n");
    return 0;
  }
  num = tmp->data;
  *top = (*top)->link;
  free(tmp);
  return num;
}

int main(void)
{
  stack *top = NULL;
  push(&top, 10);
  push(&top, 20);
  push(&top, 30);
 
  printf("%d\n", pop(&top));
  return 0;
}