c++ - 结构和指针的成员，C++

Question

我有以下代码片段:

struct Node
{
    Node* left;
    Node* right;
    string data;
};    

void test()
    {
        Node thing;
        thing.data = "h";
        thing.left = NULL;
        thing.right = NULL;

        cout<< "Thing data = " << thing.data << endl;

        Node* thing2;
        thing2->data = "f";
        thing2->left = NULL;
        thing2->right = NULL;

        cout<< "Thing2 data = " << thing2->data << endl;

    }

我遇到的问题是 thing2->data = "f"在运行时产生了段错误。我已经通过 GDB 运行该程序并收到此错误，但我无法弄清楚它的含义:

Reading symbols for shared libraries ++. done Thing data = h

Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: 13 at address: 0x0000000000000000 0x00007fff874d59a3 in std::string::assign ()

任何帮助都会很棒。谢谢!

Answer 1

thing2 是一个未初始化的指针。 它没有指向有效的 Node 对象。

你应该分配它:

thing2 = new Node;

或者让它指向一个有效的节点对象:

thing2 = & thing;