typeid和typeinfo

typeid

运行时获知变量类型名称，返回值为type_info类型，可以使用 typeid(变量).name()

#include<iostream>
#include<string>
#include<typeinfo>
using namespace std;

class AA{

};

int main() {
    // typeid 用于自定义的数据类型
    AA aa;
    AA *paa = &aa;
    AA &raa = aa;
    cout << "typeid(AA) = " << typeid(AA).name()<<endl;
    cout << "typeid(aa) = " << typeid(aa).name()<<endl;
    cout << "typeid(AA *) = " << typeid(AA *).name()<<endl;
    cout << "typeid(paa) = " << typeid(paa).name()<<endl;
    cout << "typeid(AA &) = " << typeid(AA &).name()<<endl;
    cout << "typeid(raa) = " << typeid(raa).name()<<endl;

    // type_info重载了==和!= 运算符，用于对类型进行比较
    if (typeid(AA) == typeid(aa))
    {
        cout << " aa is AA instance "<<endl;
    }
    return 0;
}