stack_usinglist.c

#include <stdio.h>
#include <stdlib.h>

struct Stack{
	int size;
	struct List{
		int item;
		struct List *next;
	} *head;
};
typedef struct Stack *slink;

slink create_stack(void){
	slink stack=malloc(sizeof(struct Stack));
	if(!stack)
		return stack;
	stack->size=0;
	stack->head=NULL;
	return stack;
}

int empty(slink stack){
	return stack->size==0;
}

void push_stack(slink stack,int item){
	struct List *new=malloc(sizeof(struct List));
	if(!new)
		return;
	new->item=item;
	new->next=stack->head;
	stack->head=new;
	stack->size++;
}

int pop_stack(slink stack){
	if(empty(stack))
		return -1;
	struct List *torm=stack->head;
	int retval=stack->head->item;
	stack->head=stack->head->next;
	free(torm);
	stack->size--;
	return retval;
}

int main(){
	slink stack=create_stack();
	int data[]={1,2,3,4,5,6,7,8,9};
	int i=0;
	while(i<6)
		push_stack(stack,data[i++]);
	while(!empty(stack))
		printf("%d\n",pop_stack(stack) );
	while(i<9)
		push_stack(stack,data[i++]);
	while(!empty(stack))
		printf("%d\n",pop_stack(stack) );
}