将类构造函数重载INSIDE在同一个类的另一个重载中

Question

嘿,所以我正在使用Windows GetTickCount()和STL进行秒表课程,但遇到了一个问题,即在将Stopwatch(int DecNumb)构造函数实现到重载Stopwatch(int DecNumb,char command [])时在后一个构造函数中未正确设置"准确性"数据类型.

(它似乎返回到unsigned long int 560345的前值或者其他东西......)

这是我用来测试它的class和main()命令:

class Stopwatch
    {
    protected:
        int               accuracy;
        unsigned long int initial_ilu;
        unsigned long int current_ilu;
        long float        output_fl;
       vector<long float> times;

    public:
        Stopwatch(int DecNumb) { // so accuracy*10 isn't 0
                                    accuracy = 1;
                                for(;DecNumb>0;DecNumb--) // the Tick count will
                                accuracy = accuracy*10;}; // diveded by accuracy (each 0 in this number moves the decimal over once)
        Stopwatch(int aDecNumb, char command[]) {Stopwatch::Stopwatch(aDecNumb);
                                                 if(command = "start") Stopwatch::Start();}; 
        void Start(){initial_ilu = GetTickCount()/*/accuracy*/;};
        long float ElapsedTime()
        {
            current_ilu = GetTickCount()/*/accuracy*/;
            output_fl =  (current_ilu - initial_ilu)/accuracy;
            return output_fl;
        };
        void Wait(long float seconds) 
        {
            for(unsigned long int waitTime = GetTickCount() + (seconds*accuracy);
                waitTime > GetTickCount();) {}
            // stay stuck in for loop until time specified is up
        };

        void SaveTime(){times.push_back(GetTickCount()/*/accuracy*/);};
        long float GetTime(int location){if(times.size()<location+1) return times[location+1];
                                         else return -1;};

    };

这里是主要的()

int main()
    {
        Stopwatch myStopwatch(3,"start");
        for(;;)
        {
            myStopwatch.Wait(2);
            cout << myStopwatch.ElapsedTime() << endl;
        }
                return 0;
    }

为什么精度不能保持在我在构造函数中设置的值？谢谢!=) 哦,欢迎任何其他反馈我的代码!(我很新)

Answer 1

Stopwatch::Stopwatch(aDecNumb);

这不会调用其他构造函数; 它甚至不是有效的C++.

您不能从另一个构造函数中为同一个对象调用一个构造函数.在创建对象期间只调用一个构造函数(当然不包括基类或成员构造函数).

但是,你并不需要两个构造函数; 一个就足够了:

Stopwatch(int DecNumb, char* command = 0) {
    accuracy = 1;
    for(; DecNumb > 0; DecNumb--) {
        accuracy = accuracy * 10;
    }

    if (command && std::string(command) == "start") {
        Start();
    }
}

如果你真的需要两个构造函数,最好的办法是使用一个执行多个构造函数通用的初始化的基类,或者使用可以从多个构造函数调用的"初始化"成员函数.