Бинарное дерево

#include <iostream.h>
#include <vcl.h>
#pragma hdrstop
//---------------------------------------------------------------------------
#pragma argsused
 
struct Node{
int d;
Node *left;
Node *right;
};
Node *first (int d);
Node *search_insert(Node *root, int d);
void print_tree(Node *root, int l);
int main(){
int b[] = {10, 25, 20, 6, 21, 8, 1, 30};
Node *root = first(b[0]);
for (int i = 1; i<8; i++)search_insert(root, b[i]);
print_tree(root, 0);
return 0;}
 
Node *first (int d){
Node *pv = new Node;
pv->d = d;
pv->left = 0;
pv->right = 0;
return pv;
}
 
Node *search_insert(Node *root, int d) {
Node *pv = root *prev;
bool found = false;
while (pv && !found){
prev = pv;
if (d == pv->d) found = true;
else if (d < pv->d) pv =pv->left;
else pv = pv->right;}
if (found) return pv;
Node *pnew = new Node;
pnew->d = d;
pnew->left = 0;
pnew->right = 0;
if (d < prev->d)
prev->left == pnew;
else
prev->right = pnew;
return pnew;
}
 
void print_tree(Node *p, int level){
if (p){
print_tree(p->left, level +1); // вывод левого поддерева
for (int i = 0; i<level; i++)cout << " ";
cout << p->d << endl; // вывод корня поддерева
print_tree(p->right, level +1); // вывод правого поддерева
}
}

while (pv && !found){
prev = pv;
if (d == pv->d) found = true;
else if (d < pv->d) pv =pv->left;
else pv = pv->right;}
if (found) return pv;

Node *pnew = new Node;
pnew->d = d;
pnew->left = 0;
pnew->right = 0;
if (d < prev->d)
prev->left == pnew;
else
prev->right = pnew;

Node *search_insert(Node *root, int d)
{
    Node *pv = root, *prev; // Естественно, тут запятая...
    bool found = false;
    while (pv && !found)
    {
        prev = pv;
        if (d == pv->d) found = true;
        else if (d < pv->d)
            pv = pv->left;
        else
            pv = pv->right;
    }
    if (found)
        return pv;
    Node *pnew = new Node;
    pnew->d = d;
    pnew->left = 0;
    pnew->right = 0;
    if (d < prev->d)
        prev->left = pnew; // А вот тут - присваивание, а не сравнение !!!
    else
        prev->right = pnew;
    return pnew;
}

Node *pv = root, *prev;