demo_type_cast_1_typeid_1.cpp

对于一个初涉VC＋＋的人来书

//*****************************************************
// 使用typeid操作符支持C++运行时类型信息(RTTI)特征
// 此时必须包含typeinfo.h头文件,
// 并启用RTTI编译选项Enable Run-Time Type Information
//*****************************************************

# include <iostream.h>
# include <typeinfo.h>

class Control {}; //定义一个空类

int main()
{
	//Display name of type
	Control ct;
	if(typeid(ct)==typeid(Control))
		cout<<"ct is Class Control type"<<endl;
	cout<<"ct is "<<typeid(ct).name()<<" type"<<endl;

	//Compare typeids and display type of expression
	double counter=1.23;
	if(typeid(counter)!=typeid(Control))
		cout<<"counter is not "<<typeid(Control).name()<<" type"<<endl;
	if(typeid(counter)!=typeid(int))
		cout<<"counter is not int type"<<endl;
	if(typeid(counter)==typeid(1.23))
		cout<<"counter is double type"<<endl;

	return 0;
}

/*
ct is class Control type
counter is not class Control type
counter is not int type
counter is double type
Press any key to continue
*/