feat: update cpp files

Author: lulongfei

explicit.cpp

@@ -0,0 +1,30 @@
+#include <iostream>
+
+class A
+{
+
+public:
+    A() = default;
+    explicit A(int t_height)
+    : height(t_height)
+    {}
+
+    void GetHeight()
+    {
+        std::cout << height << std::endl;
+    }
+
+private:
+    int height;
+
+};
+
+
+int main()
+{
+
+    // A c = 95; // error, 因为A的构造函数加了explicit，只能是显示地转换，不能是隐式转换
+    A c = (A)98; // corrent，只能显示地转换
+    c.GetHeight();
+    return 0;
+}

mem_model.cpp

@@ -0,0 +1,67 @@
+#include <iostream>
+
+typedef struct Point3
+{
+    float x;
+    float y;
+    float z;
+} BigPoint3;
+
+
+class Point3d
+{
+    public:
+    Point3d(float x= 0.0, float y = 0.0, float z=  0.0)
+    :_x(x),_y(y),_z(z){}
+
+    float x() const {return _x;}
+    float y() const {return _y;}
+    float z() const {return _z;}
+
+    private:
+    float _x;
+    float _y;
+    float _z;
+};
+
+
+inline std::ostream& operator<<(std::ostream& os, const Point3d& pt)
+{
+    os << "Point3d(" << pt.x() << ", " << pt.y() << ", " << pt.z() << ")";
+    return os;
+}
+
+class Base
+{
+    public:
+    Base(int i): baseI(i){};
+    virtual void print(void){std::cout << "调用了虚函数Base::print()";}
+    virtual void setI(){std::cout << "调用了虚函数Base::setI";}
+    virtual ~Base(){}
+    public:
+    int baseI;
+};
+
+
+int main()
+{
+    // BigPoint3 a = {1,2,3};
+    // std::cout << (&a) << std::endl;
+    // std::cout << &(a.x) << std::endl;
+    // std::cout << *((float *)(&a)) << std::endl;
+    // std::cout << *((float *)(&a)+1) << std::endl;
+    // std::cout << *((float *)(&a)+2) << std::endl;
+
+    // Point3d b{2, 4, 9};
+    // std::cout << b << std::endl;
+    typedef void(* Func)(void);
+
+    Base b(1000);
+    std::cout << ((int *)(&b)) << std::endl;
+    std::cout << ((int *)(&b.baseI)) << std::endl;
+    std::cout << (int *)*(int *)(&b) << std::endl;
+    Func vfunc = (Func)*((int *)*(int *)(&b));
+    vfunc();
+
+    // getchar();
+}