puneeth node cur,cur1;
cur=first;
cur1=first;
while(cur1!=null)
{
cur=cur->link;
cur1=cur1->link;
cur1=cur1->link;
}
printf("middle node is %d",cur->info);

puneeth 1. take two references to first node like,
cur=first and cur1=first.
2. wen cur is traversed once ,let cur1 to traverse twice so that when
cur1 is at the end of list cur will be pointing to middle of the list.