网站建设需要的技术路线,百度问问我要提问,北京到安阳高速费多少钱,网站开发与应用案例教程我们知道C可以对函数进行重载#xff0c;让同名的函数来完成相同的基本操作。其实运算符也是可以重载的#xff0c;而且有的运算符已经在使用了#xff0c;就像*#xff0c;既可以用于地址#xff0c;又可以用于乘法。
下面是一个计算时间的类
#ifndef MYTIME_H
#define…我们知道C可以对函数进行重载让同名的函数来完成相同的基本操作。其实运算符也是可以重载的而且有的运算符已经在使用了就像*既可以用于地址又可以用于乘法。
下面是一个计算时间的类
#ifndef MYTIME_H
#define MYTIME_H#include iostreamusing namespace std;class Time
{
private:int hours;int minutes;public:Time();Time(int h, int m 0);void AddMin(int m);void AddHr(int h);void Reset(int h 0, int m 0);Time Sum(const Time t) const;void Show() const;
};#endif // MYTIME_H#include mytime.hTime::Time()
{hours minutes 0;
}Time::Time(int h, int m)
{hours h;minutes m;
}void Time::AddMin(int m)
{minutes m;hours minutes/60;minutes % 60;
}void Time::AddHr(int h)
{hours h;
}void Time::Reset(int h, int m)
{hours h;minutes m;
}Time Time::Sum(const Time t) const
{Time sum;sum.minutes minutes t.minutes;sum.hours hours t.hours sum.minutes/60;sum.minutes % 60;return sum;
}void Time::Show() const
{cout hours hours, minutes minutes.\n;
} #include iostream
#include mytime.husing namespace std;int main()
{Time planning;Time coding(2, 40);Time fixing(5, 55);Time total;cout planning time ;planning.Show();cout endl;cout coding time ;coding.Show();cout endl;cout fixing time ;fixing.Show();cout endl;total coding.Sum(fixing);cout coding.Sum(fixing) ;total.Show();cout endl;return 0;
}
输出结果
planning time 0 hours, 0 minutes.coding time 2 hours, 40 minutes.fixing time 5 hours, 55 minutes.coding.Sum(fixing) 8 hours, 35 minutes.
添加加法运算符
将Time类转换为重载的加法运算法很容易只要将Sum()的名称改为operator ()即可。只要把运算符放在operator的后面
#ifndef STOCK_H
#define STOCK_H
#include stringusing namespace std;class stock
{
private:string company;long shares;double share_val;double total_val;void set_tot() {total_val shares * share_val;}public:void buy(long num, double price);void sell(long num, double price);void update(double price);void show() const;const stock topval(const stock s) const;stock(const string co, long n, double pr);stock();~stock();
};#endif // STOCK_H#include mytime.hTime::Time()
{hours minutes 0;
}Time::Time(int h, int m)
{hours h;minutes m;
}void Time::AddMin(int m)
{minutes m;hours minutes/60;minutes % 60;
}void Time::AddHr(int h)
{hours h;
}void Time::Reset(int h, int m)
{hours h;minutes m;
}//运算符重载
Time Time::operator(const Time t) const
{Time sum;sum.minutes minutes t.minutes;sum.hours hours t.hours sum.minutes/60;sum.minutes % 60;return sum;
}void Time::Show() const
{cout hours hours, minutes minutes.\n;
}
operator(const Time t) const与Sum(const Time t) const效果完全一样可以理解operator()就是一个函数也可以被调用。就像下面的语句一样。
total coding.operator(fixing);
但是可以进一步简化
total coding fixing; 这两种方法都讲使用operator()函数运算符左侧的coding是调用对象右边的fixing是参数被传递的对象。
#include iostream
#include mytime.husing namespace std;int main()
{Time planning;Time coding(2, 40);Time fixing(5, 55);Time total;cout planning time ;planning.Show();cout endl;cout coding time ;coding.Show();cout endl;cout fixing time ;fixing.Show();cout endl;//total coding.operator(fixing);total coding fixing;cout coding.Sum(fixing) ;total.Show();cout endl;return 0;
}输出结果没有变化
planning time 0 hours, 0 minutes.coding time 2 hours, 40 minutes.fixing time 5 hours, 55 minutes.coding.Sum(fixing) 8 hours, 35 minutes. 运算符重载的限制
1、重载后的运算符必须至少有一个操作数是用户定义的类型
2、使用运算符使不能违反运算符原来的句法规则
3、不能创建新的运算符
4、有些运算符不能被重载如sizeof, ?:, ::等
5、大多数运算符都可以通过成员或者非成员函数进行重载但、、[]、-只能通过成员函数进行重载。 、-、 *重载的应用
#ifndef MYTIME_H
#define MYTIME_H#include iostreamusing namespace std;class Time
{
private:int hours;int minutes;public:Time();Time(int h, int m 0);void AddMin(int m);void AddHr(int h);void Reset(int h 0, int m 0);Time operator(const Time t) const;Time operator-(const Time t) const;Time operator*(double mult) const;void Show() const;
};#endif // MYTIME_H
#include mytime.hTime::Time()
{hours minutes 0;
}Time::Time(int h, int m)
{hours h;minutes m;
}void Time::AddMin(int m)
{minutes m;hours minutes/60;minutes % 60;
}void Time::AddHr(int h)
{hours h;
}void Time::Reset(int h, int m)
{hours h;minutes m;
}//运算符重载
Time Time::operator(const Time t) const
{Time sum;sum.minutes minutes t.minutes;sum.hours hours t.hours sum.minutes/60;sum.minutes % 60;return sum;
}Time Time::operator-(const Time t) const
{Time diff;int tot1, tot2;tot1 t.minutes 60 * t.hours;tot2 minutes 60 * hours;diff.minutes (tot2 - tot1) % 60;diff.hours (tot2 - tot1) / 60;return diff;
}Time Time::operator*(double mult) const
{Time result;long totalminutes hours * mult *60 minutes * mult;result.hours totalminutes / 60;result.minutes totalminutes % 60;return result;
}void Time::Show() const
{cout hours hours, minutes minutes.\n;
}
#include iostream
#include mytime.husing namespace std;int main()
{Time weeding(4, 35);Time waxing(2, 47);Time total;Time diff;Time adjusted;cout weeding time ;weeding.Show();cout endl;cout waxing time ;waxing.Show();cout endl;cout total working time ;total weeding waxing;total.Show();cout endl;diff weeding - waxing;cout weeding time - waxing time ;diff.Show();cout endl;adjusted total * 1.5;cout adjusted work time ;adjusted.Show();cout endl;return 0;
}输出结果
weeding time 4 hours, 35 minutes.waxing time 2 hours, 47 minutes.total working time 7 hours, 22 minutes.weeding time - waxing time 1 hours, 48 minutes.adjusted work time 11 hours, 3 minutes.
