Linked list Implementation with a return type of node*

#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();   //Point the next pointer to the next node 
                       //whose address is returned recursively.
 return head;          //return the pointer to the current node
}

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