【c++】第十二周上机实践作业 项目 2

/*

*copyright(c) 2016,烟台大学计算机学院

*All rights reserved

*文件名称：test.cpp

*作者：谭泽纯

*版本：v6.0

*

*问题描述：

实现Time类中的运算符重载。

<code class="hljs cpp has-numbering"><span class="hljs-keyword">class</span> CTime
{
<span class="hljs-keyword">private</span>:
<span class="hljs-keyword">unsigned</span> <span class="hljs-keyword">short</span> <span class="hljs-keyword">int</span> hour;    <span class="hljs-comment">// 时</span>
<span class="hljs-keyword">unsigned</span> <span class="hljs-keyword">short</span> <span class="hljs-keyword">int</span> minute;  <span class="hljs-comment">// 分</span>
<span class="hljs-keyword">unsigned</span> <span class="hljs-keyword">short</span> <span class="hljs-keyword">int</span> second;  <span class="hljs-comment">// 秒</span>
<span class="hljs-keyword">public</span>:
CTime(<span class="hljs-keyword">int</span> h=<span class="hljs-number">0</span>,<span class="hljs-keyword">int</span> m=<span class="hljs-number">0</span>,<span class="hljs-keyword">int</span> s=<span class="hljs-number">0</span>);
<span class="hljs-keyword">void</span> setTime(<span class="hljs-keyword">int</span> h,<span class="hljs-keyword">int</span> m,<span class="hljs-keyword">int</span> s);
<span class="hljs-keyword">void</span> display();
<span class="hljs-comment">//二目的比较运算符重载</span>
<span class="hljs-keyword">bool</span> <span class="hljs-keyword">operator</span> > (CTime &t);
<span class="hljs-keyword">bool</span> <span class="hljs-keyword">operator</span> < (CTime &t);
<span class="hljs-keyword">bool</span> <span class="hljs-keyword">operator</span> >= (CTime &t);
<span class="hljs-keyword">bool</span> <span class="hljs-keyword">operator</span> <= (CTime &t);
<span class="hljs-keyword">bool</span> <span class="hljs-keyword">operator</span> == (CTime &t);
<span class="hljs-keyword">bool</span> <span class="hljs-keyword">operator</span> != (CTime &t);

<span class="hljs-comment">//二目的加减运算符的重载</span>
<span class="hljs-comment">//返回t规定的时、分、秒后的时间</span>
<span class="hljs-comment">//例t1(8,20,25),t2(11,20,50)，t1+t2为19:41:15</span>
CTime <span class="hljs-keyword">operator</span>+(CTime &t);
CTime <span class="hljs-keyword">operator</span>-(CTime &t);<span class="hljs-comment">//对照+理解</span>
CTime <span class="hljs-keyword">operator</span>+(<span class="hljs-keyword">int</span> s);<span class="hljs-comment">//返回s秒后的时间</span>
CTime <span class="hljs-keyword">operator</span>-(<span class="hljs-keyword">int</span> s);<span class="hljs-comment">//返回s秒前的时间</span>
<span class="hljs-comment">//二目赋值运算符的重载</span>
CTime &<span class="hljs-keyword">operator</span>+=(CTime &c);
CTime &<span class="hljs-keyword">operator</span>-=(CTime &c);
CTime &<span class="hljs-keyword">operator</span>+=(<span class="hljs-keyword">int</span> s);<span class="hljs-comment">//返回s秒后的时间</span>
CTime &<span class="hljs-keyword">operator</span>-=(<span class="hljs-keyword">int</span> s);<span class="hljs-comment">//返回s秒前的时间</span>
<span class="hljs-comment">//一目运算符的重载</span>
CTime <span class="hljs-keyword">operator</span>++(<span class="hljs-keyword">int</span>);<span class="hljs-comment">//后置++，下一秒</span>
CTime &<span class="hljs-keyword">operator</span>++();<span class="hljs-comment">//前置++，下一秒</span>
CTime <span class="hljs-keyword">operator</span>--( <span class="hljs-keyword">int</span>);<span class="hljs-comment">//后置--，前一秒</span>
CTime &<span class="hljs-keyword">operator</span>--();<span class="hljs-comment">//前置--，前一秒</span>
};</code><ul style="" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li><li>16</li><li>17</li><li>18</li><li>19</li><li>20</li><li>21</li><li>22</li><li>23</li><li>24</li><li>25</li><li>26</li><li>27</li><li>28</li><li>29</li><li>30</li><li>31</li><li>32</li><li>33</li><li>34</li><li>35</li><li>36</li></ul><ul style="" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li><li>16</li><li>17</li><li>18</li><li>19</li><li>20</li><li>21</li><li>22</li><li>23</li><li>24</li><li>25</li><li>26</li><li>27</li><li>28</li><li>29</li><li>30</li><li>31</li><li>32</li><li>33</li><li>34</li><li>35</li><li>36</li></ul>

　　提示1：并不是所有比较运算重载函数都很复杂

<code class="hljs cs has-numbering"><span class="hljs-comment">//比较运算返回的是比较结果，是bool型的true或false</span>
<span class="hljs-comment">//可以直接使用已经重载了的运算实现新运算，例如果已经实现了 > ，则实现 <= 就可以很方便了……</span>
<span class="hljs-keyword">bool</span> CTime::<span class="hljs-keyword">operator</span> <= (CTime &t) <span class="hljs-comment">// 判断时间t1<=t2</span>
{
<span class="hljs-keyword">if</span> (*<span class="hljs-keyword">this</span> > t) <span class="hljs-keyword">return</span> <span class="hljs-keyword">false</span>;
<span class="hljs-keyword">return</span> <span class="hljs-keyword">true</span>;
}</code><ul style="" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li></ul><ul style="" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li></ul>

　　甚至可以如下面的代码般简练：

<code class="hljs cs has-numbering"><span class="hljs-keyword">bool</span> CTime::<span class="hljs-keyword">operator</span> <= (CTime &t){<span class="hljs-keyword">return</span> !(*<span class="hljs-keyword">this</span> > t)}</code><ul style="" class="pre-numbering"><li>1</li></ul><ul style="" class="pre-numbering"><li>1</li></ul>

　　提示2：并不是所有复合赋值运算重载函数都需要很复杂

<code class="hljs cs has-numbering"><span class="hljs-comment">//可以直接使用已经重载了的加减运算实现</span>
<span class="hljs-comment">//这种赋值, 例如 t1+=20，直接改变当前对象的值，所以在运算完成后，将*this作为返回值</span>
CTime &CTime::<span class="hljs-keyword">operator</span>+=(CTime &c)
{
*<span class="hljs-keyword">this</span>=*<span class="hljs-keyword">this</span>+c;
<span class="hljs-keyword">return</span> *<span class="hljs-keyword">this</span>;
}</code><ul style="" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li></ul><ul style="" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li></ul>

　　提示3：请自行编制用于测试的main()函数，有些结果不必依赖display()函数，提倡用单步执行查看结果

*/

答案

#include <iostream>

using namespace std;

class CTime

{

private:

unsigned short int hour; // 时

unsigned short int minute; // 分

unsigned short int second; // 秒

public:

CTime(int h=0,int m=0,int s=0);

void setTime(int h,int m,int s);

//输入输出运算的重载

friend istream &operator>>(istream &in,CTime &t);

friend ostream &operator<<(ostream &out,CTime t);

//比较运算符(二目)的重载

bool operator > (CTime &t);

bool operator < (CTime &t);

bool operator >= (CTime &t);

bool operator <= (CTime &t);

bool operator == (CTime &t);

bool operator != (CTime &t);

//二目运算符的重载

CTime operator+(CTime &c);//返回c所规定的时、分、秒后的时间，例t1(8,20,25),t2(11,20,50)，t1+t2为:41:15

CTime operator-(CTime &c);//对照+理解

CTime operator+(int s);//返回s秒后的时间

CTime operator-(int s);//返回s秒前的时间

//一目运算符的重载

CTime operator++(int);//后置++，下一秒

CTime &operator++();//前置++，下一秒

CTime operator--(int);//后置--，前一秒

CTime &operator--();//前置--，前一秒

//赋值运算符的重载

CTime &operator+=(CTime &c);

CTime &operator-=(CTime &c);

CTime &operator+=(int s);//返回s秒后的时间

CTime &operator-=(int s);//返回s秒前的时间

};

CTime::CTime(int h,int m,int s)

{

hour=h;

minute=m;

second=s;

}

void CTime::setTime(int h,int m,int s)

{

hour=h;

minute=m;

second=s;

}

//!!!

ostream &operator<<(ostream &out,CTime t)

{

out<<t.hour<<':'<<t.minute<<':'<<t.second;

return out;

}

bool CTime::operator > (CTime &t)

{

if (hour>t.hour) return true;

if (hour<t.hour) return false;

if (minute>t.minute) return true;

if (minute<t.minute) return false;

if (second>t.second) return true;

return false;

}

bool CTime::operator < (CTime &t)

{

if (hour<t.hour) return true;

if (hour>t.hour) return false;

if (minute<t.minute) return true;

if (minute>t.minute) return false;

if (second<t.second) return true;

return false;

}

bool CTime::operator == (CTime &t)

{

if (*this<t || *this>t)

return false;

return true;

}

bool CTime::operator != (CTime &t)

{

if (*this==t) return false;

return true;

}

bool CTime::operator >= (CTime &t)

{

if (*this<t) return false;

return true;

}

bool CTime::operator <= (CTime &t)

{

if (*this>t) return false;

return true;

}

CTime CTime::operator + (CTime &t)

{

int h,m,s;

s=second+t.second;

m=minute+t.minute;

h=hour+t.hour;

if (s>59)

{

s-=60;

m++;

}

if (m>59)

{

m-=60;

h++;

}

while (h>23) h-=24;

CTime t0(h,m,s);

return t0;

}

CTime CTime::operator+(int s)

{

int ss=s%60;

int mm=(s/60)%60;

int hh=s/3600;

CTime t0(hh,mm,ss);

return *this+t0;

}

CTime CTime::operator - (CTime &t)

{

int h,m,s;

s=second-t.second;

m=minute-t.minute;

h=hour-t.hour;

if (s<0)

{

s+=60;

m--;

}

if (m<0)

{

m+=60;

h--;

}

while (h<0) h+=24;

CTime t0(h,m,s);

return t0;

}

/////////////////////////老师方法更妙

CTime CTime::operator-(int s)

{

int ss=s%60;

int mm=(s/60)%60;

int hh=s/3600;

CTime t0(hh,mm,ss);

return *this-t0;

}

////////////////////区分引用和非引用。 一个是返回自己，一个是重新返回一个类

CTime CTime::operator++(int)

{

CTime t=*this;

*this=*this+1;

return t;

}

CTime &CTime::operator++()

{

*this=*this+1;

return *this;

}

CTime CTime::operator--(int)

{

CTime t=*this;

*this=*this-1;

return t;

}

CTime &CTime::operator--()

{

*this=*this-1;

return *this;

}

CTime &CTime::operator+=(CTime &c)

{

*this=*this+c;

return *this;

}

CTime &CTime::operator-=(CTime &c)

{

*this=*this-c;

return *this;

}

CTime &CTime::operator+=(int s)

{

*this=*this+s;

return *this;

}

CTime &CTime::operator-=(int s)

{

*this=*this-s;

return *this;

}

////////////使用老师的进行测试（》》运载符没用）

int main()

{

CTime t1,t2,t;

cout<<"t1为：";

CTime t1(1,2,3);

cout<<"t2为：";

CTime t2(4,5,6);

cout<<"下面比较两个时间大小：\n";

if (t1>t2) cout<<"t1>t2"<<endl;

if (t1<t2) cout<<"t1<t2"<<endl;

if (t1==t2) cout<<"t1＝t2"<<endl;

if (t1!=t2) cout<<"t1≠t2"<<endl;

if (t1>=t2) cout<<"t1≥t2"<<endl;

if (t1<=t2) cout<<"t1≤t2"<<endl;

cout<<endl;

cout<<"t1= "<<t1<<endl;

cout<<"t2= "<<t2<<endl;

cout<<"t=t1++"<<endl;

t=t1++;

cout<<"t= "<<t<<" t1= "<<t1<<endl;

cout<<"t=++t1"<<endl;

t=++t1;

cout<<"t= "<<t<<" t1= "<<t1<<endl;

cout<<"t1+t2= "<<t1+t2<<endl;

cout<<"t1-t2= "<<t1-t2<<endl;

cout<<"t1+2000= "<<t1+2000<<endl;

cout<<"t1-5000= "<<t1-5000<<endl;

return 0;

}

ostream & operator<<(ostream &out,CTime t)

{

out<<t.hour<<" "<<t.minute<<" "<<t.second;

return out;

}

//二目的比较运算符重载

bool CTime::operator > (CTime &t)

{

if (hour>t.hour) return true;

if (hour<t.hour) return false;

if (minute>t.minute) return true;

if (minute<t.minute) return false;

if (second>t.second) return true;

return false;

}

bool CTime::operator < (CTime &t)

{

if (hour<t.hour) return true;

if (hour>t.hour) return false;

if (minute<t.minute) return true;

if (minute>t.minute) return false;

if (second<t.second) return true;

return false;

}

bool CTime::operator == (CTime &t)

{

if(hour==t.hour&&minute==t.minute&&second==t.second)

return true;

else

return false;

}

bool CTime::operator >= (CTime &t)

{

if(*this<t)

return false;

else

return true;

}

bool CTime::operator <= (CTime &t)

{

if(*this>t)

return false;

else

return true;

}

bool CTime::operator != (CTime &t)

{

if(*this!=t)

return true;

else

return false;

}

//二目的加减运算符的重载

//返回t规定的时、分、秒后的时间

//例t1(8,20,25),t2(11,20,50)，t1+t2为19:41:15

CTime CTime::operator+(CTime &t)

{

int h,m,s,qw;

h=hour+t.hour;

m=minute+t.minute;

s=second+t.second;

if(s>=60)

{

qw=s/60;

s=s%60;

m=m+qw;

}

if(m>=60)

{

qw=m/60;

m=m%60;

h=h+qw;

}

if(h>23)

h=h-24;

return CTime(h,m,s);

}

CTime CTime::operator-(CTime &t)

{

int h,m,s;

s=second-t.second;

m=minute-t.minute;

h=hour-t.hour;

if (s<0)

{

s+=60;

m--;

}

if (m<0)

{

m+=60;

h--;

}

while (h<0) h+=24;

CTime t0(h,m,s);

return t0;

}

CTime CTime::operator+(int s) //!!!!用前面的

{

int ss=s%60;

int mm=(s/60)%60;

int hh=s/3600;

CTime tt(hh,mm,ss);

return *this+tt;

}

CTime CTime::operator-(int s)

{

int ss=s%60;

int mm=(s/60)%60;

int hh=s/3600;

CTime tt(hh,mm,ss);

return *this-tt;

}

CTime &CTime::operator+=(CTime &c)

{

*this=*this+c;

return *this;

}

CTime &CTime::operator-=(CTime &c)

{

*this=*this-c;

return *this;

}

CTime &CTime::operator+=(int s)

{

*this=*this+s;

return *this;

}

CTime &CTime::operator-=(int s)

{

*this=*this-s;

return *this;

}

CTime CTime::operator++(int)

{

CTime t=*this;

*this=*this+1;

return t;

}

CTime &CTime::operator++()

{

*this=*this+1;

return *this;

}

CTime CTime::operator--( int)

{

CTime t=*this;

*this=*this-1;

return t;

}

CTime &CTime::operator--()

{

*this=*this-1;

return *this;

}

int main()

{

CTime t;

cout<<"t1为：";

CTime t1(1,2,3);

cout<<"t2为：";

CTime t2(4,5,6);

cout<<"下面比较两个时间大小：\n";

if (t1>t2) cout<<"t1>t2"<<endl;

if (t1<t2) cout<<"t1<t2"<<endl;

if (t1==t2) cout<<"t1＝t2"<<endl;

if (t1!=t2) cout<<"t1≠t2"<<endl;

if (t1>=t2) cout<<"t1≥t2"<<endl;

if (t1<=t2) cout<<"t1≤t2"<<endl;

cout<<endl;

cout<<"t1= "<<t1<<endl;

cout<<"t2= "<<t2<<endl;

cout<<"t=t1++"<<endl;

t=t1++;

cout<<"t= "<<t<<" t1= "<<t1<<endl;

cout<<"t=++t1"<<endl;

t=++t1;

cout<<"t= "<<t<<" t1= "<<t1<<endl;

cout<<"t1+t2= "<<t1+t2<<endl;

cout<<"t1-t2= "<<t1-t2<<endl;

cout<<"t1+2000= "<<t1+2000<<endl;

cout<<"t1-5000= "<<t1-5000<<endl;

return 0;

}