Insert function in C Binary Tree?

Question

My Binary Tree code in C isn't running at all and I'm not sure exactly why. Is there anything blatantly wrong in the function? It runs with just one insert use, but any more and it stops working. It's just supposed to be a simple function that inserts ints at their right place along the tree.

#include <stdio.h>
#include <stdlib.h>


typedef struct trees Tree;
struct trees {
    int data;
    Tree *left;
    Tree *right;
};

Tree *inicio=NULL; 


void insert(int n){
        Tree *novo = (Tree*)malloc(sizeof(Tree));
        Tree *aux;
        Tree *pai;

        novo->data=n;
        novo->left=NULL;
        novo->right=NULL;
    if(inicio==NULL){
            inicio = novo;
            return;
    } else {
        aux = inicio;
        pai = NULL;
        while(1){
            pai = aux;
            if(n>pai->data){
                aux=aux->right;
                if(aux==NULL){
                    pai->right=novo;
                    return;
            } else {
                aux=aux->left;
                if(aux==NULL){
                    pai->left=novo;
                    return;
                }

            }
            }
        }
    }   
}

int main() {
    insert(9);
    insert(8);

    printf("[%p] -> (%p, %d, %p)\n",inicio,inicio->left,inicio->data,inicio->right);    

    return 0;
}

Answer 1

to illustrate @kaylum point, here is the relevant part reformatted

while(1){
    pai = aux;
    if(n>pai->data){
        aux=aux->right;
        if(aux==NULL){
            pai->right=novo;
            return;
        } // end if(aux==NULL)
        else
        {  // else => aux != NULL
           aux=aux->left;
           if(aux==NULL){
               pai->left=novo;
               return;
           } // end if(aux==NULL)
        } // end else
    } // end if(n>pai->data)
} // end while

Please Note that else after return are pointless noise

while(1){
    pai = aux;
    if(n > pai->data){
        aux = aux->right;
        if(aux == NULL){
            pai->right = novo;
            return;
        }
        continue; // skip to next loop
    }
    // implying (n <= pai->data)
    aux = aux->left;
    if(aux == NULL){
        pai->left = novo;
        return;
    }
}

"Better" implementation would probably use pointer to pointer and reduce redundant code.

void insert(int n)
{
    Tree **pp = &inicio;

    while (*pp)
    {
        if ((*pp)->data < n)
            pp = &(*pp)->right;
        else
            pp = &(*pp)->left;
    }

    *pp = malloc(sizeof **pp);
    if (*pp)
    {
        (*pp)->data = n;
        (*pp)->left = (*pp)->right = NULL;
    }
}