error in location

[xtoma]

i have this problem
i insert 10 as first location then 20 and 30
when i run the program it give me error in location
10 30 20

the error may be in insert can you give me hints for this
thank you in advance

 Node * List::InsertNode (int index , double x)
 {                
                      if (index < 0 )return NULL;
                      int currlndex = 1 ;
                      Node* currNode = head;
                      while (currNode!= NULL && index > currlndex ) 
                      {
                            currNode;
                            currlndex++;
                       }
                            if (index > 0 && currNode == NULL ) return NULL;
                            Node*newNode = new Node;
                            newNode -> data = x;
                            if (index ==0)
                            {
                                   newNode -> next = head;
                                  head = newNode;
                                   }
                                  
                      
                            else
                                           {
                                           newNode -> next = currNode->next;
                                           currNode->next = newNode ;
                                           }
                                           return newNode;
    }

[weaknessforcats]

Usually, the first node of a list is index 0. So 10 20 30 would be indexes 0 1 and 2. It's done this way so the list works like an array, which everyone is familiar with.

Next, in what order did you enter your values? If you went 10,20,30 the all you need is append at end of list. But if you went 20 30 10 and you want to keep the list sorted then you need an insert node A before node B. That is usually a function:

void insertbefore(Node*A, Node* B);

where A is inserted before B.