/*
*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;
}