论函数的设计应如何才好，返回临时变量 | 返回引用 | 传递引用

class tempTest{
public:
    tempTest(){
        cout <<"hello tempTest() "<<count++ << endl; 
    }
    tempTest(tempTest& ){
        cout <<"hello copy tempTest() "<<count++ << endl; 
    }
    ~tempTest(){
        cout << "good bye "<<count--<<endl;
    }
    tempTest& operator=(tempTest& r){
        cout <<"hello operator= "<<count++ << endl; 
        return *this;
    }
private:
    static int count;
};
int tempTest::count = 0;

tempTest testTemp(){
    tempTest t;
    return t;
}

        cout << " tt = testTemp"<<endl;
        //这样写，就3次构造函数
        tempTest tt;
        tt = testTemp();

        cout << "tempTest tt = testTemp"<<endl;
        //这样写，就2次构造函数
        tempTest tt2 = testTemp();

tempTest& testTemp2(){
    tempTest * t = new tempTest();
    return *t;
}

        cout << "tempTest& tt = testTemp"<<endl;
        tempTest& tt3 = testTemp2();
        _CrtDumpMemoryLeaks();
        delete &tt3;

void testTemp3(tempTest& t){

}

        cout << "testTemp3(tempTest&)"<<endl;
        tempTest tt4;
        testTemp3(tt4);