c++ - 奇怪的结构访问错误

Question

基本上我有这段代码:

#include <iostream>
using namespace std;

    struct foo{
        string *question;
        //other elements
    };

    int main(){
        foo *q;
        foo *q2;
        q->question = new string("This is a question"); 
        //q2->question = new string("another question");
    }

当我取消注释 q2->question = new string("another question"); 时，它出错了，我不知道为什么。

更新: 该错误是一条 Windows 消息，指出程序已停止工作并打印 Process exited with return value 3221225477

Answer 1

您的 q 和 q2 指针未初始化。您正在尝试访问尚未分配的内存。作为短期修复:

int main(){
    foo *q = new foo;
    foo *q2 = new foo;
    q->question = new string("This is a question"); 
    q2->question = new string("another question");

    // don't forget to release the memory you allocate!
    delete q->question;
    delete q2->question;
    delete q;
    delete q2;

}

在这种情况下更好的解决方案是不使用指针……完全没有必要。使用栈，不需要处理指针，也不需要释放内存。

int main(){
    string q1 = "This is a question";
    string q2 = "another question";
}