Binary Tree Einfügemethode verursacht Stapelüberlauf

Question

Das Problem

ich einige Zweifel mit meiner Methode zum Einfügen in C++ mit, es verursacht einen Stapelüberlauf.

Zusammengestellt mit g ++ auf Windows

g ++ -Wall -O2 Tree.cpp -o Baum

Ausgang

0 [unknown (0x2B70)] Baum 10496 cygwin_exception :: open_stackdumpfile: Versenkung Stack-Trace Tree.exe.stackdump

-Code

# include <iostream> 

using namespace std; 

struct Node{ 

    int val; 
    Node *left, *right; 

}; 

Node* Insert(Node *node, int val) 
{ 

    if(node == NULL) 
    { 
     node = new Node; 
     node->val = val; 
     node->right = node->left = NULL; 
    } 

if(node->val > val) 
    node->left = Insert(node->left, val); 
else 
    node->right = Insert(node->right, val); 

return node; 

} 

int main() 
{ 

Node *root = NULL; // New tree 

root = Insert(root, 5); 
root = Insert(root, 19); 
root = Insert(root, 1); 
root = Insert(root, 32); 
return 0; 
} 

Answer 1

Y Sie müssen die Rekursion stoppen, wenn sie NULL erreicht hat.

Try this:

Node* Insert(Node *node, int val) 
{ 

    if(node == NULL) 
    { 
     node = new Node; 
     node->val = val; 
     node->right = node->left = NULL; 
    } 

    else if(node->val > val) // add "else" here 
     node->left = Insert(node->left, val); 
    else 
     node->right = Insert(node->right, val); 

    return node; 

} 

Answer 2

The problem in your function is, you are trying to access null memory. 
Please check my comments here 

/* You are checking for node == null, which is correct. */ 
if(node == NULL) 
    { 
     node = new Node; 
     node->val = val; 
     node->right = node->left = NULL; 
    } 


    /* Consider what will happen when node is null, you are still trying to access null memory. You need to put else if here to avoid control to fall into this condition if node is null. */ 
    if(node->val > val) // add "else" here 
     node->left = Insert(node->left, val); 
    else 
     node->right = Insert(node->right, val);