#include
        
         #include 
         
          #include
          
           using namespace std;/** * url:http://www.cplusplus.com/doc/tutorial/other_data_types/ *//** * in which all its member elements occupy the same physical space in memory. * The size of this type is the one of the largest member element */union mytypes_t{    char c;    int i;    float f;} mytypes;/** * 枚举类,注意不是枚举类型,语法如下 *///They are declared with enum class (or enum struct) instead of just enum:enum class Colors    : long    {        black, blue, green};enum Color2{    black2, blue2, green2, white};enum class EyeColor    : char    {    blue, green, brown};//大神解说 https://zhuanlan.zhihu.com/p/21722362//enum Color//{//    //编译出错,重新定义white//    black, white, red//equals this//#define black 0//#define white 1//#define red 2//};//that is okenum  class Color{
           black, white, red};//        auto white = false; // errortemplate
           
             void f(T t){    using tt = T;    tt t2;    t2 = t;    typedef T ttt;    ttt t3 = t;}int main(){    /**     * 类型别名     * 继承自c     * typedef existing_type new_type_name;     * c++     * using new_type_name=existing_type     */    typedef char C_1;    C_1 c = 'A';    using C_2 = char;    C_2 cc = 'B';    f(10);    Colors mycolor;    mycolor = Colors::black;    if(mycolor == Colors::black)    {        mycolor = Colors::blue;    }    //只有一个字节长度噢    cout << sizeof(EyeColor) << endl;    cout << sizeof(Colors) << endl;    cout << sizeof(Color2) << endl;    return 0;}