Error inserting data in binary tree

Question

I copied this code (in spanish) http://www.elrincondelc.com/nuevorincon/index.php?pag=codigos&id=4 and wrote a new one.

This is my code:

#include <cstdlib>
#include <conio.h>
#include <iostream>

using namespace std;

struct nodoarbol {
    int dato;
    struct nodoarbol *izq;
    struct nodoarbol *der;
};

typedef nodoarbol Nodo;

typedef Nodo *Arbol;

void insertar(Arbol *, int);
void inorden(Arbol);
void postorden(Arbol);
void preorden(Arbol);

void insertar(Arbol *raiz, int nuevo){
    if (*raiz==NULL){
        *raiz = (Nodo *)malloc(sizeof(Nodo));
        if (*raiz != NULL){
            (*raiz)->dato=nuevo;
            (*raiz)->der=NULL;
            (*raiz)->izq=NULL;
        }
        else{
            cout<<"No hay memoria suficiente u ocurrio un error";
        }
    }
    else{
        if (nuevo < (*raiz)->dato)
            insertar( &((*raiz)->izq), nuevo  );
        else if (nuevo > (*raiz)->dato)
            insertar(&((*raiz)->der), nuevo);
    }
}//inseertar

void inorden(Arbol raiz){
    if (raiz != NULL){
        inorden(raiz->izq);
        cout << raiz->dato << " ";
        inorden(raiz->der);
    }
}

void preorden(Arbol raiz){
    if (raiz != NULL){
        cout<< raiz->dato << " ";
        preorden(raiz->izq);
        preorden(raiz->der);
    }
}

void postorden(Arbol raiz){
    if (raiz!=NULL){
        postorden(raiz->izq);
        postorden(raiz->der);
        cout<<raiz->dato<<" ";

    }
}

int main() {
    int i;
    i=0;
    int val;
    Arbol raiz = NULL;
    for (i=0; i<10; i++){
        cout<<"Inserte un numero";
        cin>>val;
        insertar( (raiz), val);
    }
    cout<<"\nPreorden\n";
    preorden(raiz);
    cout<<"\nIneorden\n";
    inorden(raiz);
    cout<<"\nPostorden\n";
    postorden(raiz);
    return 0;
}

I'm using netbeans 7.1.1, mingw32 compiler

This is the output:

make[2]: Leaving directory `/q/netbeans c++/NetBeansProjects/treek'
make[1]: Leaving directory `/q/netbeans c++/NetBeansProjects/treek'
main.cpp: In function 'int main()':
main.cpp:110:30: error: cannot convert 'Arbol {aka nodoarbol*}' to 'Nodo** {aka nodoarbol**}' for argument '1' to 'void insertar(Nodo**, int)'
make[2]: *** [build/Release/MinGW-Windows/main.o] Error 1
make[1]: *** [.build-conf] Error 2
make: *** [.build-impl] Error 2

BUILD FAILED (exit value 2, total time: 11s)

I don't understand what's wrong since i just copied the code (and rewrite it to my own code). I'm really good in php, asp.net (vb) and other languages but c is a headche for me.

I've been struggling with this problem for about an hour. Could somebody tell me what could it be?

Answer 1

for (i=0; i<10; i++){
        cout<<"Inserte un numero";
        cin>>val;
        insertar( (raiz), val);
    }

Should (at least) be:

for (i=0; i<10; i++){
            cout<<"Inserte un numero";
            cin>>val;
            insertar( &raiz, val);
        }

Also, your insert-function overwrites existing nodes with

if (*raiz != NULL){
(*raiz)->dato=nuevo;
(*raiz)->der=NULL;
(*raiz)->izq=NULL;
}

Update: the above statement is incorrect. The if (*raiz != NULL){} was in a subblock conditional on (*raiz ==NULL) .

An attempt (untested!) to remove the recursion.

void insertar(Arbol *raiz, int nuevo){

    while (*raiz) {
       if (nuevo == (*raiz)->dato) return;
       raiz =  (nuevo < (*raiz)->dato) 
               ? &(*raiz)->izq
               : &(*raiz)->der
               ;
        }

   *raiz = (Nodo *)malloc(sizeof(Nodo));
    if (*raiz != NULL){
        (*raiz)->dato=nuevo;
        (*raiz)->der=NULL;
        (*raiz)->izq=NULL;
        }
    else{
        cout<<"No hay memoria suficiente u ocurrio un error";
        }
    }

}//inseertar

Extra comment: the original code looks more like C than C++. (I don't do C++) In C, one would not cast the return from malloc, and preferably not hide pointers behind a typedef. In C++ (so I am told) one should not use malloc().

Answer 2

main.cpp:110:30: error: cannot convert 'Arbol {aka nodoarbol*}' to 'Nodo** {aka nodoarbol* }' for argument '1' to 'void insertar(Nodo *, int)'

void insertar(Arbol *raiz, int nuevo) { ... }

Arbol raiz = NULL;

Replace:

- insertar( (raiz), val);

with:

+ insertar( &raiz, val);