link list second last element

#include<bits/stdc++.h>
using namespace std;


struct node
{
    int a;
    struct node *next;
};
struct node* second(struct node*temp)
{


    struct node*p;
    p=temp;
    while(temp->next!=NULL)
    {
        p=temp;
        temp=temp->next;
    }
    cout<<p->a<<endl;

};



struct node *head=NULL,*temp;

int main()
{
    struct node *n1,*n2;
    n1=(struct node*) malloc (sizeof(struct node));
    cout<<"give information for n1"<<endl;
    cin>>n1->a;
    n1->next=NULL;
    head=n1;
    cout<<"give information for n2"<<endl;
    cin>>n2->a;
    n2->next=NULL;
    n1->next=n2;

    temp=head;

    second(temp);

}