c++ - 二叉树不会编译: Error 'WinMain@16'

Question

我正在使用链接列表创建二叉树的过程，下面有我的类Funtree:

template <typename T>
class funtree
{
private:
struct Node
{
    T data;
    Node *left;
    Node *right;
};
Node* GetNewNode(T data)
{
    Node* newNode = new Node();
    newNode->data = data;
    newNode->left = newNode->right = NULL;
    return newNode;

}
Node* Insert(Node* root, T data)
{
    if(root == NULL) //empty tree
    {
        root = GetNewNode(data);
        return root;
    }
    else if(data <= root->data)
    {
        root->left = Insert(root->left, data);
    }
    else
    {
        root->right = Insert(root->left, data);
    }
    return root;
}
bool Search(Node* root, int data)
{
   if(root == NULL)
        return false;
   else if (root->data == data)
    return true;
   else if (data <= root->data)
    return Search(root->left, data);
   else
    return Search(root->right, data);

和我的主要方法:

 T main()
{
    Node* root; // pointer to root node
    root = NULL; // setting tree as empty
    Insert(root,15);
    Insert(root,10);
    Insert(root,20);
    T num;
    cout<<"Enter number to be searched\n";
    cin>>num;
    if(Search(root, num) == true)
        cout<<"Found\n";
    else
        cout<<"Not Found\n";
}

我正在尝试测试我的搜索方法，以查看它是否有效，并且当我尝试编译时，只会出现错误:

main.c||undefined reference to `WinMain@16'|

该程序也是一个控制台应用程序，它们都在同一个类中，我不认为这些是问题，只是以防万一需要知道它。

编辑:

我已经更改了代码的某些部分，但会像在编译器中一样粘贴它，而不是将主函数和类分开:

#include <iostream>

using namespace std;

template <typename T>
class funtree
{
private:
struct Node
{
    T data;
    Node *left;
    Node *right;
};
Node* GetNewNode(T data)
{
    Node* newNode = new Node();
    newNode->data = data;
    newNode->left = newNode->right = NULL;
    return newNode;

}
Node* Insert(Node* root, T data)
{
    if(root == NULL) //empty tree
    {
        root = GetNewNode(data);
        return root;
    }
    else if(data <= root->data)
    {
        root->left = Insert(root->left, data);
    }
    else
    {
        root->right = Insert(root->left, data);
    }
    return root;
}
bool Search(Node* root, int data)
{
   if(root == NULL)
        return false;
   else if (root->data == data)
    return true;
   else if (data <= root->data)
    return Search(root->left, data);
   else
    return Search(root->right, data);

}

  int main()
    {
    Node* root; // pointer to root node
    root = NULL; // setting tree as empty
    Insert(root,15);
    Insert(root,10);
    Insert(root,20);
    T number;
    cout<<"Enter number to be searched\n";
    cin>>number;
    if(Search(root, number) == true)
        cout<<"Found\n";
    else
        cout<<"Not Found\n";
    }

Answer 1

您的代码中有很多问题，希望这段代码对您有所帮助

prob1:将struct Node清除为private，但尝试在main中访问它

prob2:root *作为参数在您新建节点时已更改，但没有返回新的root。将Insert定义为Node* Insert(Node*& root, T data)或将函数的返回值分配给root都可以。

prob3:main应该总是返回int

#include <iostream>
using namespace std;
template <typename T>
class funtree
{
public:
struct Node
{
    T data;
    Node *left;
    Node *right;
};
Node* GetNewNode(T data)
{
    Node* newNode = new Node();
    newNode->data = data;
    newNode->left = newNode->right = NULL;
    return newNode;

}
Node* Insert(Node* root, T data)
{
    if(root == NULL) //empty tree
    {
        root = GetNewNode(data);
        return root;
    }
    else if(data <= root->data)
    {
        root->left = Insert(root->left, data);
    }
    else
    {
        root->right = Insert(root->left, data);
    }
    return root;
}
bool Search(Node* root, int data)
{
   if(root == NULL)
        return false;
   else if (root->data == data)
    return true;
   else if (data <= root->data)
    return Search(root->left, data);
   else
    return Search(root->right, data);
}
};
int main()
{
    funtree<int> tree;
    funtree<int>::Node* root; // pointer to root node
    root = NULL; // setting tree as empty
    root = tree.Insert(root,15);
    root = tree.Insert(root,10);
    root = tree.Insert(root,20);
    int num;
    cout<<"Enter number to be seared\n";
    cin>>num;
    cout<<num;
    if(tree.Search(root, num) == true)
        cout<<"Found\n";
    else
        cout<<"Not Found\n";
    return 0;
}