stacks_using_LinkedLists

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
struct stack_node
{
    int data;
    struct stack_node* next;
    
};
int isempty(struct StackNode *root)
{
    return !root;
}
struct stack_node* add_node(int data)
{
    struct stack_node* new_node=(struct stack_node*) calloc(1,sizeof(struct stack_node));
    new_node->data=data;
    new_node->next=NULL;
    return new_node;
}

struct stack_node* push(struct stack_node* root,int data)
{
    struct stack_node* new_node=(struct stack_node*) calloc(1,sizeof(struct stack_node));
    new_node->data=data;
    new_node->next=root;
    root=new_node;
    return root;
}
struct stack_node* pop(struct stack_node* root)
{   int to_pop;
    if (isempty(root))
        return NULL;
    to_pop=root->data;
    printf("%d is popped out of stack",to_pop);
    root=root->next;
    return root;
}
int peek(struct stack_node* root)
{
    if (isempty(root))
        return NULL;
    return root->data;
}
int main()
{   struct stack_node* root=NULL;
    root=add_node(10);
    root=push(root,20);
    root=pop(root);
 
    printf("Top element is %d\n", peek(root));
}