我在使用 std::stack 从递归函数检索值时遇到问题

发布于 2024-08-31 10:47:45 字数 1012 浏览 3 评论 0原文

感谢我在这篇文章中收到的帮助：

我有一个漂亮、简洁的递归函数，可以按后缀顺序遍历树：

void Node::postfix()
{
        if (left != __nullptr) { left->postfix(); } 
        if (right != __nullptr) { right->postfix(); } 
                cout<<cargo<<"\n"; 
        return;
};

现在我需要在返回值和运算符时对其进行求值。我的问题是如何检索

它们。我尝试了 std::stack:

#include <stack> 
stack <char*> s;
void Node::postfix()
{
        if (left != __nullptr) { left->postfix(); } 
        if (right != __nullptr) { right->postfix(); } 
        s.push(cargo);
        return;
};

但当我尝试在 main() 中访问它时，

while (!s.empty())
{
    cout<<s.top<<"\n";
    s.pop;
}

出现错误：

'std::stack<_Ty>::top': 函数调用缺少参数列表；使用 '&std::stack<_Ty>::top' 创建

指向成员的指针'

我陷入困境。

很快就会出现另一个问题。

原文

Thanks to the help I received in this post:

How do I use "this" in a member function?

I have a nice, concise recursive function to traverse a tree in postfix order:

void Node::postfix()
{
        if (left != __nullptr) { left->postfix(); } 
        if (right != __nullptr) { right->postfix(); } 
                cout<<cargo<<"\n"; 
        return;
};

Now I need to evaluate the values and operators as they are returned. My problem is how to retrieve

them. I tried the std::stack:

#include <stack> 
stack <char*> s;
void Node::postfix()
{
        if (left != __nullptr) { left->postfix(); } 
        if (right != __nullptr) { right->postfix(); } 
        s.push(cargo);
        return;
};

but when I tried to access it in main()

while (!s.empty())
{
    cout<<s.top<<"\n";
    s.pop;
}

I got the error:

'std::stack<_Ty>::top': function call missing argument list; use '&std::stack<_Ty>::top' to create

a pointer to member'

I'm stuck.

Another question to follow shortly.

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寄离 2024-09-07 10:47:45

它们是成员函数：

s.top()
s.pop()
     ^ need parentheses to call a function

这就是错误显示“函数调用缺少参数列表”时的含义。参数列表（在本例中为空，因为该函数不带参数）和括号丢失。

They are member functions:

s.top()
s.pop()
     ^ need parentheses to call a function

That's what the error means when it says "function call missing argument list." The argument list (which in this case is empty since the function takes no parameters) and the parentheses are missing.

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