[C++知识库]二叉树遍历（C++）

先序遍历

class Node{
public:
    int data;
    Node* left;
    Node* right;
    
    Node(int val){
        data = val;
    }
};

// 先序遍历(递归)
void preOrder(class Node* root){
    if(root == NULL){
        return;
    }
    cout<<root->data<< "  ";
    preOrder(root->left);
    preOrder(root->right);
}

//先序遍历(非递归)
void preOrderPlus(class Node* root){
    stack<Node*> s;
    class Node* curr = NULL;
    if(root != NULL){
        s.push(root);
    }
    while(!s.empty()){
        curr = s.top();
        s.pop();
        cout<<curr->data<<"  ";
        if(curr->right != NULL){
            s.push(curr->right);
        }
        if(curr->left != NULL){
            s.push(curr->left);
        }
    }
    
}
int main()
{
    class Node* root = new Node(1);
    root->left = new Node(2);
    root->right = new Node(3);
    root->left->left = new Node(4);
    root->left->right = new Node(5);
    preOrder(root);
    cout<<"先序遍历（递归）"<<endl;
    preOrderPlus(root);
    cout<<"先序遍历(非递归)" << endl;
}

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