Question

我从以下代码开始：

#include <iostream>

class Base
{
private:
    char a[4];
public:
    Base(void){memcpy(a, "Base", 4);}
    ~Base(void){}
};

class Derived :
    public Base
{
private:
    char b[8];
public:
    Derived(void){ memcpy(b, "Derived", 8);}
    ~Derived(void){}
};

要提取基类的数据，我将执行以下操作：

int main(void)
{
    Derived derived;

    char* onlyBase = new char[sizeof(Base) + 1];//+1 for '\0'
    memcpy(onlyBase, &static_cast<Base>(derived), sizeof(Base));
    onlyBase[sizeof(Base)] = '\0';

    std::cout << onlyBase;
}

如何只获取课程派生部分的数据？

Answer 1

hacky ，它可能适用于您的情况：

char* onlyDerived = new char[sizeof(Derived) - sizeof(Base) + 1];//+1 for '\0'
memcpy(onlyDerived, &reinterpret_cast<const char*>(&derived) + sizeof(Base), sizeof(Derived) - sizeof(Base));
onlyDerived[sizeof(Derived) - sizeof(Base)] = '\0';

我不鼓励你这样做，你可能有几个问题（不是便携式......，对齐，填充，字节序......）。

您可以执行以下操作：char* Base::serialize() const;。

如何隔离派生类的数据（序列化）？

1 个答案: