C++ 指针经过的指针不';行不通
我有一个非常简单的程序,我想创建一个二叉树并打印它。 但是,下面显示的代码段不会改变树结构C++ 指针经过的指针不';行不通,c++,parameter-passing,C++,Parameter Passing,我有一个非常简单的程序,我想创建一个二叉树并打印它。 但是,下面显示的代码段不会改变树结构 //binary_tree.h file typedef struct node node; struct node { node():left(0), right(0), value(-1){}; ~node(){if(left) delete left; if(right) delete right;}; node *left; node *right; int
//binary_tree.h file
typedef struct node node;
struct node
{ node():left(0), right(0), value(-1){};
~node(){if(left) delete left; if(right) delete right;};
node *left;
node *right;
int value;
};
inline void insert_node(node **root, node *new_node)
{
assert(new_node != NULL);
if(*root == NULL)
{
*root = new_node;
}
else
{
node *itr = *root;
while(1)
{
if(itr->value > new_node->value)
itr = itr->left;
else
itr = itr->right;
if(!itr)
{
itr = new_node;
break;
}
}
}
}
inline void inorder_print(node *root)
{
if(!root) return;
inorder_print(root->left);
printf("%d\n", root->value);
inorder_print(root->right);
}
//main.cpp file
#include "binary_tree.h"
int main()
{
node *node1 = new node();
node *node2 = new node();
node *node3 = new node();
node *node4 = new node();
node *node5 = new node();
node1->value = 5;
node2->value = 10;
node3->value = 3;
node4->value = 1;
node5->value = 4;
node *binary_tree = NULL;
insert_node(&binary_tree, node1);
insert_node(&binary_tree, node2);
insert_node(&binary_tree, node3);
insert_node(&binary_tree, node4);
insert_node(&binary_tree, node5);
assert(binary_tree != NULL);
inorder_print(binary_tree);
return 0;
}
按顺序打印函数始终打印“5”
问题是使用“itr”变量。我真的不知道如何在不使用局部变量或不更改指向根的指针的情况下做到这一点 插入例程将只在根目录中插入一个节点
node *itr = *root;
while(1)
{
if(itr->value > new_node->value)
itr = itr->left;
else
itr = itr->right;
if(!itr)
{
itr = new_node;
break;
}
}
由于itr
是一个局部变量,new\u节点
实际上没有被插入。您可以通过将itr
设置为指向类似于根的指针来纠正此问题
if(!itr)
{
itr = new_node;
break;
}
使用std::set。您的代码似乎是旧的C代码。是C++:
node **itr = root;
while(1)
{
if((*itr)->value > new_node->value)
itr = &(*itr)->left;
else
itr = &(*itr)->right;
if(!*itr)
{
*itr = new_node;
break;
}
}
#包括
#包括
int main()
{
std::set二叉树;
二叉树插入(5);
二叉树插入(10);
二叉树插入(3);
二叉树插入(1);
二叉树插入(4);
//有序打印(二叉树);
对于(std::set i=binary_tree.begin();i!=binary_tree.end();++i)
标准::cout
#include <set>
#include <iostream>
int main()
{
std::set<int> binary_tree;
binary_tree.insert(5);
binary_tree.insert(10);
binary_tree.insert(3);
binary_tree.insert(1);
binary_tree.insert(4);
//inorder_print(binary_tree);
for (std::set<int> i = binary_tree.begin(); i != binary_tree.end(); ++i)
std::cout << *i << std::endl;
}