Reverse a linked list

#include <iostream>
#include <algorithm>
#include <cstdlib>

using namespace std;

typedef struct node{
 int data;
 node *next;
};

node *allocate(){
 node *ptr = (node *)malloc(sizeof(node));
 ptr -> next = NULL;
 return ptr;
}

node *f(){
 int x;
 cin >> x;
 if(x == -1)
 return NULL;
 node *head = allocate();
 head ->data = x;
 head ->next = f();
 return head;
}

node *rev(node **curr, node *last){
 if((*curr)->next == NULL){
 (*curr)->next = last;
 return (*curr);
 }
 node *temp = rev(&((*curr)->next), *curr);
 if(last != NULL)
 (*curr)->next = last;
 else
 (*curr)->next = NULL;
 return temp;
}

int main()
{
 cout << "Enter items of list:-\nType -1 to exit.\n";
 node *head;
 head = NULL;
 head = f();
 node *temp = head;
 cout << "old list is \n";
 while(temp!= NULL)
 cout << temp->data << " ", temp = temp->next;
 head = rev(&head, NULL);
 cout << endl;
 temp = head;
 cout << "New list is \n";
 while(temp!= NULL)
 cout << temp->data << " ", temp = temp->next;
 return 0;
}