c++ - 在 C++ 中获取 "this"(当前实例)的拷贝

Question

我想要一个当前正在运行的实例的拷贝。

当我更改拷贝中的值时，原始对象也会受到影响。拷贝充当实例。

如何避免这种情况？我需要创建调用对象的独立拷贝。

 Set operator+(Set s){
             Set temp = *this;  

             for(int i=0; s.elements[i] != '\0'; i++){
                     temp(s.elements[i]);
             }
             temp.elements[0] = 'X'; // <- this affects calling object also :(

             return temp;

         }

Answer 1

问题在于 Set temp = *this; 进行的是浅拷贝，而不是深拷贝。您必须修改 Set 类的复制构造函数和赋值运算符，以便它们复制所有成员/包含的对象。

例如:

class Set
{
public:
    Set()
    {
        elements = new SomeOtherObject[12];
        // Could make elements a std::vector<SomeOtherObject>, instead
    }

    Set(const Set& other)
    {
        AssignFrom(other);
    }

    Set& operator=(const Set& other)
    {
        AssignFrom(other);
        return *this;
    }

private:
    void AssignFrom(const Set& other)
    {
        // Make copies of entire array here, as deep as you need to.
        // You could simply do a top-level deep copy, if you control all the
        // other objects, and make them do top-level deep copies, as well
    }

    SomeOtherObject* elements;
};