chap6_运算符重载.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,算术运算符：加（,+,）、减,string s1,s2;/s1,s2,为字符串对象,s1+s2/?,CComplex,a,b,;/,复数类对象,a+b,/?,a-b/?,x+y/x,y,为,int,float,double,char,.,问题引出：,运算符重载,#include,class,CComplex,public:,CComplex(double,rt,=0,double it=0);,void,disp,();,void,set(double,double,);,void,get(double&,double,CComplex,add(CComplex,CComplex,dec(CComplex,private:,double,r,i,;,;,CComplex:CComplex(double,rt,double,it),r=,rt;i,=it;,void,CComplex:set(double,rt,double,it),r=,rt;i,=it;,void,CComplex:get(double,&,rt,double,&it),rt,=,r;it,=i;,void,CComplex:disp,(),if(,r|r,=0&i=0),cout,0&r),cout,+;,if(i),if(i=1);,else if(i=-1),cout,-;,else,cout,i;,cout,i;,cout,endl,;,CComplex,CComplex:add(CComplex,&t),return,CComplex(r+t.r,i+t.i,);,CComplex,CComplex:dec(CComplex,&t),return,CComplex(r-t.r,i-t.i,);,void main(),CComplex,a(10,10),b(15,15),c;,a.disp,();,b.disp,();,c=,a.add(b,);,c.disp,();,c=,a.dec(b,);,c.disp,();,10+10i,15+15i,25+25i,-5-5i,c=,a+b,;,c=a-b;,complex1,问题引出：自定义类型的运算,void main(),CComplex,a(10,10),b(15,15),c;,a.disp,();,b.disp,();,c=,a+b,;,c.disp,();,c=a-b;,c.disp,();,编译器将其解释为函数调用：,c=,a.,operator+,(b,);,c=,a.,operator-,(b,);,定义了两个重载运算符的成员函数，它们的名字是：,operator+,operator,complex2,#include,class,CComplex,public:,CComplex(double,rt,=0,double it=0);,void,disp,();,void,set(double,double,);,void,get(double&,double,CComplex,operator+,(,CComplex,CComplex,operator-,(,CComplex,private:,double,r,i,;,;,CComplex:CComplex(double,rt,double,it),r=,rt;i,=it;,void,CComplex:set(double,rt,double,it),r=,rt;i,=it;,void,CComplex:get(double,&,rt,double,&it),rt,=,r;it,=i;,void,CComplex:disp,(),if(,r|r,=0&i=0),cout,0&r),cout,+;,if(i),if(i=1);,else if(i=-1),cout,-;,else,cout,i;,cout,i;,cout,endl,;,CComplex,CComplex:,operator,+,(,CComplex,&t),return,CComplex(r+t.r,i+t.i,);,CComplex,CComplex:,operator,-,(,CComplex,&t),return,CComplex(r-t.r,i-t.i,);,#include,class,CPoint,public:,CPoint(int,xx=0,int,yy,=0),x=xx;y=,yy,;,void,disp,(),cout,(x,y)”,既作为流的插入运算符，又作为移位运算符，根据其操作对象的不同，执行其不同的功能。,在,c+,中，允许对大多数的运算符进行重载，通过,定义重载运算符的函数,使它能够用于特定类的对象。,运算符重载的实现,运算符重载实际上是将运算符重载为一个函数，在重载某个运算符时，实际上就是定义一个,重载运算符的函数,，函数名为,operator,运算符,。在执行被重载的运算符时，系统自动调用该函数以实现相应的运算,对表达式,a+b,、,ab,，编译器将其解释为函数调用：,a.operator,+(b);,a.operator,(b);,运算符重载是通过定义函数实现的，运算符重载实质上是函数的重载（遵循函数重载的原则）。,对于重载的运算符可以使用运算符方式调用，也可以使用函数调用方式调用。,CComplex,CComplex:,operator,+,(,CComplex,&t),return,CComplex(r+t.r,i+t.i,);,CComplex,CComplex:,operator,-,(,CComplex,&t),return,CComplex(r-t.r,i-t.i,);,重载运算符的函数的定义形式,friend,返回类型,类名,:,operator,重载的运算符（参数列表）,相关操作；,参数的个数由以下两个因素决定：,1,操作符是,单目,还是,双目运算符,2,定义为友元函数还是成员函数,友元函数,成员函数,单目运算符,1,个参数,0,个参数,双目运算符,2,个参数,1,个参数,在,C+,中提供了两种形式的运算符重载，即重载为：,成员函数、友元函数,如果是友元函数，那么对于,单目运算符,，它的参数个数就是,1,个，,双目运算符,的参数个数是,2,个；如果是成员函数，那么对于,单目运算符,的参数个数为,0,，,双目运算符,的参数个数是,1,个（,这是由于调用该成员函数的对象本身也作为一个操作数参与计算）。,一、重载为类的成员函数,类中的函数原型声明：,返回类型,operator,重载的运算符,（参数类型列表）,;,程序中出现（以双目运算符为例）,C1,运算符,C2,C1,.,operator,运算符,(C2),编译程序解释为函数调用：,其中，,C1,和,C2,是类的对象，,operator,运算符,则是,运算符重载函数名。,1,、双目运算重载为成员函数：,1,个参数,定义形式：,返回类型,类名,:,operator,重载的运算符,（参数列表）,相关操作；,对表达式,a+b,、,ac,，编译器将其解释为函数调用：,a.operator,+(b);,a.operator,(c);,Complex,Complex:,operator,+,(Complex&t),return,Complex(r+t.r,i+t.i,);,Complex,Complex:,operator,-,(Complex&t),return,Complex(r-t.r,i-t.i,);,Complex,operator+,(Complex,Complex,operator-,(Complex,operator,运算符,是,重载运算符的函数名。,#include,class,CComplex,public:,CComplex(double,rt,=0,double it=0);,void,disp,();,void,set(double,double,);,void,get(double&,double,CComplex,operator+,(,CComplex,CComplex,operator-,(,CComplex,CComplex,operator+=,(,CComplex,private:,double,r,i,;,;,CComplex:CComplex(double,rt,double,it),r=,rt;i,=it;,void,CComplex:set(double,rt,double,it),r=,rt;i,=it;,void,CComplex:get(double,&,rt,double,&it),rt,=,r;it,=i;,void,CComplex:disp,(),if(,r|r,=0&i=0),cout,0&r),cout,+;,if(i),if(i=1);,else if(i=-1),cout,-;,else,cout,i;,cout,i;,cout,endl,;,CComplex,CComplex:,operator,+,(,CComplex,&t),return,CComplex(r+t.r,i+t.i,);,CComplex,CComplex:,operator,-,(,CComplex,&t),return,CComplex(r-t.r,i-t.i,);,CComplex,operator+=(,CComplex,&b),r+=,b.r,;i+=,b.i,;,return*this,;,void main(),CComplex,a(2,3),b(4,5);,CComplex,c(a+b,);,a.disp,();,b.disp,();,c.disp,();,c=a-b;,c.disp,();,a+=c;,a.disp,();,复数的运算符重载,(,成员函数,),2+3i,4+5i,6+8i,-2-2i,i,a.operator,+(b),a.operator,-(b),a.operator,+=(c),此时不再创建新对象,this,指针,是一个无需定义的特殊指针，它隐含于类的每一个,(,非静态,),成员函数中，指向调用该成员函数的当前对象。,如果某个对象调用了一个成员函数，则系统首先将这个对象的地址赋给,this,指针，因此可以用,*,this,来标识调用该成员函数的当前对象。,complex3,#include,#include,class string,public:,string(const,char*);,string(string,string();,int,strlength,();,void,disp,();,string operator=(string,string operator+(string,int,strcomp(string,int,operator(string,private:,char*,pstr,;,int,length;,;,string:string(const,char*sp),length=,strlen(sp,);,pstr,=new char length+1;,strcpy(pstr,sp,);,string:string(string,&sp),length=,sp.length,;,pstr,=new char length+1;,strcpy(pstr,sp.pstr,);,string:string,(),delete,pstr,;,int,string:strlength,(),return length;,void,string:disp,(),cout,pstr,(string&sp),if(,strcomp(sp,)0)return 1;,elsereturn 0;,void main(),string s1(1234567890);,string s2(abcdefg);,s1.disp();,s2.disp();,int,k=s1s2;,cout,ks1;,cout,k,endl,;,s1=s1+s2;,s1.disp();,s1=s2;,s1.disp();,s1.operator=(s1.operator+(s2),s1.operator=(s2),string1,注意,关于“”赋值运算：,C+,允许同类对象间的赋值,，将其对应的数据成员赋值；如果在构造函数中有资源申请，则不能使用系统的赋值方式，而必须重载赋值运算符，如,string,类；没有资源分配，可不重载赋值运算符，如,CComplex,类。,不能自造运算符：如字符串的比较函数，没有相应的运算符，不能用户自己定义。,返回类型 类名,:,operator,-(),相关操作；,2,、单目运算重载为成员函数：无参数,1,）负号运算符,#include,class,CComplex,public:,CComplex(double,rt,=0,double it=0);,void,disp,();,void,set(double,double,);,void,get(double&,double,CComplex,operator+,(,CComplex,CComplex,operator-,(,CComplex,CComplex,operator+=,(,CComplex,CComplex,operator-,();/,对单目负号重载,private:,double,r,i,;,;,CComplex,CComplex:,operator,-,()/,对单目负号重载,/,第一个,Complex,为函数返回值类型，第二个,Complex,为类名,return,CComplex(-r,-i,);,#include,class,CComplex,public:,CComplex(double,rt,=0,double it=0);,void,disp,();,void,set(double,double,);,void,get(double&,double,CComplex,operator+,(,CComplex,CComplex,operator-,(,CComplex,CComplex,operator+=,(,CComplex,CComplex,operator-,();/,对单目负号重载,private:,double,r,i,;,;,CComplex:CComplex(double,rt,double,it),r=,rt;i,=it;,void,CComplex:set(double,rt,double,it),r=,rt;i,=it;,void,CComplex:get(double,&,rt,double,&it),rt,=,r;it,=i;,void,CComplex:disp,(),if(,r|r,=0&i=0),cout,0&r),cout,+;,if(i),if(i=1);,else if(i=-1),cout,-;,else,cout,i;,cout,i;,cout,endl,;,CComplex,CComplex:,operator,+,(,CComplex,&t),return,CComplex(r+t.r,i+t.i,);,CComplex,CComplex:,operator,-,(,CComplex,&t),return,CComplex(r-t.r,i-t.i,);,CComplex,operator+=(,CComplex,&b),r+=,b.r,;i+=,b.i,;,return*this,;,CComplex,CComplex:,operator,-,(),return,CComplex(-r,-i,);,完整程序,void main(),CComplex,a(2,-3),b;,b=-a;,a.disp,();,b.disp,();,complex4,+,分：先增和后增,返回类型 类名,:,operator,+,（）,相关操作；,先增：,后增：,返回类型 类名,:,operator,+,（,int,）,相关操作；,int,只是为了标志前后的区别，没有其他作用。,2,、单目运算重载为成员函数,2,）自增,+,、自减,-,#include,class,CPoint,public:,CPoint(int,xx=0,int,yy,=0),x=xx;y=,yy,;,void,disp,(),cout,(x,y),endl,;,CPoint,operator+(,CPoint,q),return,CPoint(x+q.x,y+q.y,);,CPoint,operator-(,CPoint,q),return,CPoint(x-q.x,y-q.y,);,CPoint,operator+()/,先增,x+;y+;return*this;,CPoint,operator+(,int,)/,后增,CPoint,t(x,y,);x+;y+;return t;,CPoint,operator-(),x-;y-;return*this;,CPoint,operator-(,int,),CPoint,t(*this);x-;y-;return t;,private:,int,x,y,;,;,void main(),CPoint,a(10,10),b;,a.disp,();,b=a+;,a.disp,();,b.disp,();,b=+a;,a.disp,();,b.disp,();,b=a-;,a.disp,();,b.disp,();,b=-a;,a.disp,();,b.disp,();,(10,10),(11,11),(10,10),(12,12),(12,12),(11,11),(12,12),(10,10),(10,10),point2,this,指针的使用,*,this,3,、下标运算符,重载为成员函数：数组类,#include,class,CArray,public:,CArray(int,size);,CArray(CArray,CArray,();,int,getAt(int,nIndex,);,void,setAt(int,nIndex,int,newElement,);,int,&operator(,int,);,void operator=(,CArray,private:,int,*data;/,整型数组首地址,int,size;,/,数组中的元素个数,;,CArray:CArray(int,s),size=s;,data=new,intsize,;,CArray:CArray,(),delete data;,CArray:CArray(CArray,&a),size=,a.size,;,data=new,intsize,;,for(,int,i=0;i,size;i,+),datai,=,a.datai,;,int,CArray:getAt(int,nIndex,),return,datanIndex,;,void,CArray:setAt(int,nIndex,int,newElement,),datanIndex,=,newElement,;,int,&,CArray:operator,(,int,nIndex,),return,datanIndex,;,void,CArray:,operator,=,(,CArray,&a),delete data;,size=,a.size,;,data=new,intsize,;,for(,int,i=0;i,size;i,+),datai,=,a.datai,;,void main(),CArray,a(10);,for(,int,i=0;i10;i+),ai,=i*2+1;,for(i=0;i10;i+),cout,ai,t;,cout,endl,;,array1,#include,template,class,CArray,public:,CArray(int,size);,CArray(CArray,CArray,();,AB,getAt(int,nIndex,);,void,setAt(int,nIndex,AB,newElement,);,AB,&operator(,int,);,void operator=(,CArray,private:,AB,*data;/,整型数组首地址,int,size;,/,数组中的元素个数,;,template,CArray,:,CArray(int,s),size=s;,data=new,AB,size,;,template,CArray,:,CArray,(),delete data;,template,CArray,:,CArray(CArray,&a),size=,a.size,;,data=new,AB,size,;,for(,int,i=0;i,size;i,+),datai,=,a.datai,;,template,AB,CArray,:,getAt(int,nIndex,),return,datanIndex,;,template,void,CArray,:,setAt(int,nIndex,AB,newElement,),datanIndex,=,newElement,;,template,AB,&,CArray,:operator(,int,nIndex,),return,datanIndex,;,template,void,CArray,:,operator=,(,CArray,&a),delete data;,size=,a.size,;,data=new,AB,size,;,for(,int,i=0;i,size;i,+),datai,=,a.datai,;,void main(),int,n=10;,CArray,a(,n,);,CArray,b,(,n,);,for(,int,i=0;i,n,;i,+),ai,=i*2+1;,b,i,=i*2,.1,+1;,for(i=0;i,n,;i,+),cout,ai,t;,for(i=0;i,n,;i,+),cout,b,i,t;,array2,class string,public:,string(const,char*);,string(string,string();,void,disp,();,char&operator(,int,);,private:,char*,pstr,;,int,length;,;,char&,string:operator,(,int,i),return,pstri,;,字符串类：下标运算符,void main(),string s1(1234567890);,s1.disp();,cout,s15,输出,必须重载为友元,复数的双目运算符重载,(,友元函数,),2+3i,4+5i,6+8i,-2-2i,i,#include,class,CComplex,public:,CComplex,(double a=0,double b=0);,void,disp,();,friend,CComplex,operator+(,CComplex,&,CComplex,friend,CComplex,operator-(,CComplex,&,CComplex,friend,CComplex,operator+=(,CComplex,&,CComplex,private:,double,r,i,;,;,CComplex:CComplex,(double,a,double,b),r=,a,i,=b;,void,CComplex:disp,(),if(,r|r,=0&i=0),cout,0&r),cout,+;,if(i),if(i=1);,else if(i=-1),cout,-;,else,cout,i;,cout,i;,cout,endl,;,CComplex,operator+(,CComplex,&,a,CComplex,&b),return,CComplex(a.r+b.r,a.i+b.i,);,CComplex,operator-(,CComplex,&,a,CComplex,&b),return,CComplex(a.r-b.r,a.i-b.i,);,CComplex,operator+=(,CComplex,&,a,CComplex,&b),a.r,+=,b.r,;,a.i,+=,b.i,;return a;,void main(),CComplex,a(2,3),b(4,5);,CComplex,c(a+b,);,a.disp,();,b.disp,();,c.disp,();,c=a-b;,c.disp,();,a+=c;,a.disp,();,operator-(,a,b,),operator+=(,a,c,),operator+(,a,b,),complex5,2,、复数的单目运算符重载,(,友元函数,),void main(),CComplex,a(10,10),b;,a.disp,();,b=a+;,a.disp,();,b.disp,();,b=+a;,a.disp,();,b.disp,();,b=a-;,a.disp,();,b.disp,();,b=-a;,a.disp,();,b.disp,();,10+10i,11+11i,10+10i,12+12i,12+12i,11+11i,12+12i,10+10i,10+10i,#include,class,CComplex,public:,CComplex,(double a=0,double b=0);,void,disp,();,friend,CComplex,operator+(,CComplex,&,CComplex,friend,CComplex,operator-(,CComplex,&,CComplex,friend,CComplex,operator+=(,CComplex,&,CComplex,friend,CComplex,operator+(,CComplex,friend,CComplex,operator+(,CComplex,&,a,int,);,friend,CComplex,operator-(,CComplex,friend,CComplex,operator-(,CComplex,&,a,int,);,private:,double,r,i,;,;,CComplex:CComplex,(double,a,double,b),r=,a,i,=b;,void,CComplex:disp,(),if(,r|r,=0&i=0),cout,0&r),cout,+;,if(i),if(i=1);,else if(i=-1),cout,-;,else,cout,i;,cout,i;,cout,endl,;,CComplex,operator+(,CComplex,&,a,CComplex,&b),return,CComplex(a.r+b.r,a.i+b.i,);,CComplex,operator-(,CComplex,&,a,CComplex,&b),return,CComplex(a.r-b.r,a.i-b.i,);,CComplex,operator+=(,CComplex,&,a,CComplex,&b),a.r,+=,b.r,;,a.i,+=,b.i,;return a;,CComplex,operator+(,CComplex,&a),a.r,+;,a.i,+;return a;,CComplex,operator+(,CComplex,&,a,int,),CComplex,t(a.r+,a.i,+);return t;,CComplex,operator-(,CComplex,&a),a.r,-;,a.i,-;return a;,CComplex,operator-(,CComplex,&,a,int,),CComplex,t(a.r-,a.i,-);return t;,complex6,运算符重载的原则,运算符重载,不改变运算符的优先级和结合性,，不改变其语法结构，也就是,不能改变操作数的个数,。即单目的只能重载为单目运算符，双目的只能重载为双目运算符。,只能对已有运算符重载，不能自定义运算符,。,可重载的运算符,运算符,名,称,运,算 符,名,称,，,逗号运算符,小于,！,=,不等,左移,%,取模,=,左移,/,赋值,%=,取模,/,赋值,大于,*,乘,=,大于等于,*,=,乘,/,赋值,右移,+,加,=,右移,/,赋值,+=,加,/,赋值,异或,-,减,=,异或,/,赋值,-=,减,/,赋值,|,按位或,-,成员选取,|=,按位或,/,赋值,/,除,|,逻辑或,/=,除,/,赋值,不可重载的,5,个运算符：,.*:?:,sizeof,8-1.,定义复数类，实现复数的,+,、,-,、,+,、先,+,、后,+,、先,-,、后,-,运算符重载，使用,成员函数,和友元函数分别实现,(,两个程序,),。,8-2.,定义点类，并实现点的,+,、,-,、,+,的运算符重载：分别使用成员函数和友元函数实现,(,两个程序,),。,8-3.,定义 整型数组类，使用成员函数实现下标,运算符的重载。,8-4.,定义时间类，进行时间的自增、自减运算符重载。,8-5.*,定义字符串类，实现字符串的,+,、,=,、,=,、,等运算符的重载。,8-6.*,实现上述类型的输入输出重载（用友元函数实现）,作业8,#include,class time,private:,int,hour,minute,second,;,public:,time(int,x=0,int y=0,int z=0),hour=,x,minute,=,y,second,=y;,void,showTime,(),cout,hour:minute,:second=60),second-=60;,minute+;,if(minute,=60),minute-=60;,hour+;,hour%=24;,/,cout,=60),second-=60;,minute+;,if(minute,=60),minute-=60;,hour+;,hour%=24;,/,cout,time+n;,void main(),time mytime(23,59,59);,cout,First Time output:;,mytime.showTime,();,mytime,+;,mytime.showTime,();,+,mytime,;,mytime.showTime,();,8-4.*,定义时钟类，进行时间的自增、自减运算符重载。,