C++基础-类型转换-static_cast(基本类型转换) reinterpret_cast(指针类型转换) const_cast(const数据转换) dynamic_cast(父类子类转换)

1.static_cast基本类型转换

int main1()
{
    //printf("%d", 10.2);
    //printf("%f", (float)1); //printf不会完成数据类型转换
    //printf("%d", static_cast<int>(10.2)); //默认转换
    printf("%f", static_cast<float >(1));
}

2.reinterpret_cast(指针类型转换)

int main2()
{
    int *pint = new int(1);
    char *pch = reinterpret_cast<char*>(pint); //指针类型转换  i

    for(int i = 0; i < 4; i++)
    {
        //显示数据,
        cout << static_cast<int>(*(pch + i)) << " "<< reinterpret_cast<void*>(pch + i) << endl;
    }
    cin.get();
}

3.const_cast(const数据类型转换)

int main3()
{
    int num[5] = {1, 2, 3, 4, 5};
    const int *p = num;
    //int *pint =reinterpret_cast<cint*>(int*)(p); reinterpret_cast不适于const
    int *pint = const_cast<int*>(p);
    for(int i = 0; i < 5; i++)
    {
        cout << pint[i] << " " << reinterpret_cast<void*>(pint + i) << endl;
    }
    cin.get();
}

4.dynamic_cast(父类子类转换)

//父类
class huahua
{
public:
    int hua1;
    virtual void run()
    {
        cout << "huahua is running" << endl;
    }
};
//子类
class xiaohua: public huahua
{
public:
    int xiaohua1;
    void run() override
    {
        cout << "xiaohuahua is playing" << endl;
    }
};

int main()
{
    huahua *pfu = new huahua;
    xiaohua *pzi = new xiaohua; //创建一个父类对象以及子类
    pfu->run();
    pzi->run();
//    huahua *phua = dynamic_cast<huahua*>(pzi); //子类对象转换为父类指针
//    cout << reinterpret_cast<void*>(phua) << endl;
//    phua->run();
    xiaohua *pxiaohua = dynamic_cast<xiaohua*>(pfu);
    cout << reinterpret_cast<void*>(pxiaohua) << endl;
    if(pxiaohua != nullptr)
    {
        pxiaohua->hua1 = 10; //访问子类继承父类对象的变量
        pxiaohua->xiaohua1 = 10;
        pxiaohua->run(); //子类的对象
        (*pxiaohua).huahua::run(); //子类中间父类的方法
    }
}