C++，四种强制类型转换，static_cast，const_cast，dynamic_cast，reinterpret_cast

 

 

#include <iostream>
using namespace std;

struct A
{
    virtual void func() { cout << "A func" << endl; }
};

struct B :public A
{
    void func() { cout << "B func" << endl; }
};

int main()
{
    cout << "C++ 类型转换：static_cast，const_cast，dynamic_cast，reinterpret_cast" << endl;

    // static_cast(数据类型之间转换)
    float num1 = 2.9;
    int num2 = static_cast<int>(num1);
    cout << "static_cast float: " << num1 << endl;
    cout << "static_cast int: " << num2 << endl;
    cout << endl;

    // const_cast(去长量化)
    int data1 = 10;
    const int* data2 = &data1;
    int* data3 = const_cast<int*>(data2);
    cout << "const_cast data3: " << *data3 << endl;
    cout << endl;

    // dynamic_cast(将父类的指针或引用转换为子类的指针或引用，父类必须要有虚函数)
    B b;
    b.func();
    
    A* a = dynamic_cast<A*>(&b);
    a->func();

    B* bb = dynamic_cast<B*>(a);
    bb->func();

    cout << endl;
    
    // reinterpret_cast(啥都行，但是不推荐)
    int n1 = 10;
    int* n2 = &n1;
    float* n3 = reinterpret_cast<float*>(n2);
    cout << "reinterpret_cast float: " << *n3 << endl;

    return 0;
}