Merge Sort on Single Linked List

#include<iostream>
#include<stdlib.h>
using namespace std;

struct Node
{
   int val;
   struct Node *next;
};
typedef struct Node node;

void splithalf(node *head,node **first,node **second)
{
   node *slow=head,*fast=head;
   
    if(head==NULL || head->next==NULL)
    {
       *first=head;
       *second= NULL;
       
    }
    else
    {
       slow=head;
       fast=head->next;
       
       while(fast!=NULL)
       {
           fast=fast->next;
           if(fast!=NULL)
           {
               slow=slow->next;
               fast=fast->next;
               
           }
           
       }
       
       *first=head;
       *second=slow->next;
       slow->next=NULL;
    }
}
node *sortedmerge(node *a,node *b)
{
   node *result=NULL;
   
   if(a==NULL)
      return b;
   else if(b==NULL)
      return a;

    
    
   if(a->val<=b->val)
   {
       result=a;
       result->next=sortedmerge(a->next,b);
       
   }
   else
   {
       result=b;
       result->next=sortedmerge(a,b->next);
       
   }
   
  return(result);
}
void mergesort(node **head_ref)
{
   node *head=*head_ref;
   node*a,*b;
   
   if(head==NULL || head->next==NULL)
     return;
     
     printf("\ncount1: mergesprt\n");
     splithalf(head,&a,&b);
     
     mergesort(&a);
     mergesort(&b);
     
     printf("\ncount2: mergesort\n");
     
     *head_ref=sortedmerge(a,b);
}


void print(node *head)
{
   while(head!=NULL)
   {
       cout<<head->val<<endl;
       head=head->next;
       
   }
   
}
int main()
{

      node *head;
      
      head=(node *)malloc(sizeof(node));
      
      head->val=10;
      
      head->next=(node *)malloc(sizeof(node));
      
      head->next->val=5;
      
      head->next->next=(node *)malloc(sizeof(node));
      
      head->next->next->val=2;
      
      head->next->next->next=NULL;
   
   cout<<"The present linked list are"<<endl;
   
   print(head);
   
       cout<<"After sorting are "<<endl;
       
       mergesort(&head);
   
   print(head);
}