//error

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

typedef int element;

typedef struct stackNode {
    element data;
    struct stackNode *link;
}stackNode;

stackNode* top;

void push(element item)
{
    stackNode* temp = (stackNode *)malloc(sizeof(stackNode));
    temp->data = item;
    temp->link = top;
    top = temp;
}

element pop()
{
    element item;
    stackNode* temp = top;

    if (top == NULL) {
        printf("\n\n Stack is Empty\n");
        return 0;
    }
    else {
        item = temp->data;
        top = temp->link;
        free(temp);
        return item;
    }
}

element peek()
{
    element item;
    if (top == NULL) {
        printf("\n\n Stack is Empty\n");
        return 0;
    }
    else {
        item = top->data;
        return item;
    }
}

void del()
{
    stackNode* temp;
    if (top == NULL) {
        printf("\n\n Stack is Empty\n");
    }
    else {
        temp = top;
        top = top->link;
        free(temp);
    }
}

void printStack()
{
    stackNode* p = top;
    printf("\n STACK [ ");
    while (p) {
        printf("%d ", p->data);
        p = p->link;
    }
    printf("] ");
}

int main(void)
{
    element item;
    top = NULL;
    printStack();
    push(1);
    printStack();
    push(2);
    printStack();
    push(3);
    printStack();

    item = peek();
    printStack();
    printf("peek top => %d", item);

    del();
    printStack();

    item = pop;
    printStack();
    printf("\t pop top => %d", item);

    item = pop();
    printStack();
    printf("\t pop top => %d", item);

    pop();

    return 0;
}