typeid 是 C++ 的关键字之一，用于获取运行时类型信息，typeid操作符的返回结果是名为type_info的标准库类型的对象的引用（在头文件typeinfo中定义）。

企业建站必须是能够以充分展现企业形象为主要目的，是企业文化与产品对外扩展宣传的重要窗口，一个合格的网站不仅仅能为公司带来巨大的互联网上的收集和信息发布平台，成都创新互联面向各种领域：成都隧道混凝土搅拌车等成都网站设计、全网营销推广解决方案、网站设计等建站排名服务。

上测试代码：

#include 
#include 
#include 
#include 
#include 
#include 

using namespace std;

int func(int a) {
    return 0;
}

typedef int(*fun_ptr)(int);

class Base {
public:
    Base() {}
};

int test_typeid1() {
    char              char_ = 'a';
    unsigned char     uchar_ = 'b';
    short             short_ = -16;
    unsigned short    ushort_ = 16;
    int               int_ = -1024;
    unsigned int      uint_ = 1024;
    float             float_ = 1.2f;
    double            double_ = 2.34;
    long              long_ = -12222;
    long long         llong_ = 12222;
    int array[10] = { 0 };
    int* array_ptr = array;
    string            string_("xiongwei");
    vector       int_vector;
    fun_ptr  f = func;
    Base              base_;
    Base* pBase = new Base;
    Base& rBase = base_;

    cout << "char_ type: " << typeid(char_).name() << std::endl;
    assert(typeid(char).name() == typeid(char_).name());

    std::cout << "uchar type: " << typeid(uchar_).name() << std::endl; // uchar type: unsigned char
    assert(typeid(unsigned char).name() == typeid(uchar_).name());

    std::cout << "short_ type: " << typeid(short_).name() << std::endl; // short_ type: short
    assert(typeid(short).name() == typeid(short_).name());

    std::cout << "ushort_ type: " << typeid(ushort_).name() << std::endl; // ushort_ type: unsigned short
    assert(typeid(unsigned short).name() == typeid(ushort_).name());

    std::cout << "int_ type: " << typeid(int_).name() << std::endl; // int_ type: int
    assert(typeid(int).name() == typeid(int_).name());

    std::cout << "uint_ type: " << typeid(uint_).name() << std::endl; // uint_ type: unsigned int
    assert(typeid(unsigned int).name() == typeid(uint_).name());

    std::cout << "float_ type: " << typeid(float_).name() << std::endl; // float_ type: float
    assert(typeid(float).name() == typeid(float_).name());

    std::cout << "double_ type: " << typeid(double_).name() << std::endl; // double_ type: double
    assert(typeid(double).name() == typeid(double_).name());

    std::cout << "long_ type: " << typeid(long_).name() << std::endl; // long_ type: long
    assert(typeid(long).name() == typeid(long_).name());

    std::cout << "llong_ type: " << typeid(llong_).name() << std::endl; // llong_ type: __int64
    assert(typeid(long long).name() == typeid(llong_).name());

    std::cout << "array[] type: " << typeid(array).name() << std::endl; // array[] type: int [10]
    assert(typeid(int[10]).name() == typeid(array).name());

    std::cout << "array_header type: " << typeid(array_ptr).name() << std::endl; // array_header type: int * __ptr64
    assert(typeid(int*).name() == typeid(array_ptr).name());

    std::cout << "string_ type: " << typeid(string_).name() << std::endl; // string_ type: class std::basic_string, class std::allocator>
    assert(typeid(std::string).name() == typeid(string_).name());

    std::cout << "int_vector type: " << typeid(int_vector).name() << std::endl; // int_vector type: class std::vector>
    assert(typeid(std::vector).name() == typeid(int_vector).name());

    std::cout << "f type: " << typeid(f).name() << std::endl; // f type : int(__cdecl*)(int)
    assert(typeid(int(*)(int)).name() == typeid(f).name());

    std::cout << "Base_ type: " << typeid(base_).name() << std::endl; // Base_ type: class Base
    assert(typeid(class Base).name() == typeid(base_).name());

    std::cout << "pBase_ type: " << typeid(pBase).name() << std::endl; // pBase_ type: class Base * __ptr64
    assert(typeid(class Base*).name() == typeid(pBase).name());

    std::cout << "rBase_ type: " << typeid(rBase).name() << std::endl; // Base__ type: class Base
    assert(typeid(class Base&).name() == typeid(rBase).name());
    return 0;

}

void test_typeid2() {

    struct Base {

    }; // non-polymorphic
    struct Derived : Base {

    };

    struct Base2 {
        virtual void foo() {}
    }; // polymorphic

    struct Derived2 : Base2 {

    };

    int myint = 50;
    std::string mystr = "string";
    double *mydoubleptr = NULL;

    std::cout << "myint has type: " << typeid(myint).name() << '\n' // myint has type: int
        << "mystr has type: " << typeid(mystr).name() << '\n' // mystr has type: class std::basic_string, class std::allocator>
        << "mydoubleptr has type: " << typeid(mydoubleptr).name() << '\n'; // mydoubleptr has type: double * __ptr64

                                                                           // std::cout << myint is a glvalue expression of polymorphic type; it is evaluated
    const std::type_info& r1 = typeid(std::cout); // 50

    std::cout << "#std::cout<>

    const std::type_info& r2 = typeid(std::printf("%d\n", myint));
    std::cout << "printf(\"%d\\n\",myint) has type : " << r2.name() << '\n'; // printf(\"%d\\n\",myint) has type : int

    Derived d1;
    Base& b1 = d1;
    std::cout << "reference to non-polymorphic base: " << typeid(b1).name() << '\n'; // reference to non-polymorphic base: struct 'int __cdecl test_typeid2(void)'::'2'::Base

    Derived2 d2;
    Base2& b2 = d2;
    std::cout << "reference to polymorphic base: " << typeid(b2).name() << '\n'; // reference to polymorphic base: struct 'int __cdecl test_typeid2(void)'::'3'::Derived2

    try {
        // dereferencing a null pointer: okay for a non-polymoprhic expression  
        std::cout << "mydoubleptr points to " << typeid(*mydoubleptr).name() << '\n'; // mydoubleptr points to double  
                                                                                      // dereferencing a null pointer: not okay for a polymorphic lvalue  
        Derived2* bad_ptr = NULL;
        std::cout << "bad_ptr points to...";  // bad_ptr points to...   
        std::cout << typeid(*bad_ptr).name() << '\n';
    }
    catch (const std::bad_typeid& e) {
        std::cout << " caught " << e.what() << '\n'; // caught Attempted a typeid of NULL pointer!  
    }

}

template < typename T >
T max(T arg1, T arg2) {
    std::cout << typeid(T).name() << "s compared." << std::endl;
    return (arg1 > arg2 ? arg1 : arg2);
}

int test_typeid3()
{
    class Base {
    public:
        virtual void vvfunc() {}
    };

    class Derived : public Base {};

    Derived* pd = new Derived;
    Base* pb = pd;
    std::cout << typeid(pb).name() << std::endl;   //prints "class Base *" // class 'int __cdecl test_typeid3(void)'::'2'::Base * __ptr64  
    std::cout << typeid(*pb).name() << std::endl;   //prints "class Derived" // class 'int __cdecl test_typeid3(void)'::'2'::Derived  
    std::cout << typeid(pd).name() << std::endl;   //prints "class Derived *" // class 'int __cdecl test_typeid3(void)'::'2'::Derived * __ptr64  
    std::cout << typeid(*pd).name() << std::endl;   //prints "class Derived" // class 'int __cdecl test_typeid3(void)'::'2'::Derived  
    delete pd;

    float a = 1.2, b = 3.4;
    max(a, b); // floats compared  

    max(1,2);

    return 0;
}

int main() {

    test_typeid1();
    cout << "---------------------------------------" << endl;
    test_typeid2();
    test_typeid3();

    system("pause");
    return 0;
}

另外有需要云服务器可以了解下创新互联scvps.cn，海内外云服务器15元起步，三天无理由+7*72小时售后在线，公司持有idc许可证，提供“云服务器、裸金属服务器、高防服务器、香港服务器、美国服务器、虚拟主机、免备案服务器”等云主机租用服务以及企业上云的综合解决方案，具有“安全稳定、简单易用、服务可用性高、性价比高”等特点与优势，专为企业上云打造定制，能够满足用户丰富、多元化的应用场景需求。

当前名称：C++typeid关键字-创新互联
网站URL：http://kswjz.com/article/eideg.html