CODEWITHSUNDEEP
c++pointersrecursiontree
ESD
ESD

Reputation: 544

Binary tree pointer error

I have three functions to managa a binary tree : 

static void insertion(Noeud* &top, Noeud *newNoeud)
{
    if(top == NULL)
        top = newNoeud;
    else if(newNoeud->nbr < top->nbr)
        insertion(top->left, newNoeud);
    else
        insertion(top->right, newNoeud);
}

static void affichage(Noeud* &top) //displaying
{
    if(top != NULL)
    {
        affichage(top->left);
        affichage(top->right);
        cout << "\n" << top->nbr;
    }
}

static Noeud* recherche(Noeud* &top, int nbr) //searching 
{
    while(top != NULL)
    {
        if(top->nbr == nbr)
            return(top);
        else if(nbr < top->nbr)
            top = top->left;
        else
            top = top->right;
    }
}

however I keep getting an error saying that I am violating the access when trying to read a memory spot. I am guessing this has to do with my pointers but I can't guess what it is.

Upvotes: 2

Views: 118

Answers (2)

Roee Gavirel
Roee Gavirel

Reputation: 19473

the recherche changes the top which it shouldn't.

Does this even compiled ?

static Noeud* recherche(Noeud* &top, int nbr) //searching 
{
    while(top != NULL)
    {
        if(top->nbr == nbr)
            return(top);
        else if(nbr < top->nbr)
            top = top->left;
        else
            top = top->right;
    }
}

This doesn't always return a value...

should be something like that:

static Noeud* recherche(Noeud* &top, int nbr) //searching 
{
    Noeud* it = top; //use a temporary pointer for the search.
    while(it != NULL)
    {
        if(it->nbr == nbr)
            return(it);
        else if(nbr < it->nbr)
            it = it->left;
        else
            it = it->right;
    }
    return it; //always return a value.
}

Upvotes: 1

GiGImushroom
GiGImushroom

Reputation: 31

Your search method makes your top node not point to top anymore.

Upvotes: 1

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