c++运算符重载.pptx

1、运算符重载使得用户自定义的数据以一种更简洁的方式工作,例如 int x , y; y = x + y ;,matrix m1 , m2 ;/ 矩阵类对象 m1 = Madd ( m1 , m2 ) ;/ 调用函数计算两个矩阵的和,complex c1 , c2 ; / 复数类对象 c1 = Cadd (c1 , c2 ) ;/ 调用函数计算两个复数的和,能表示为 c1 = c1 + c2 ; ?,能表示为 m1 = m1 + m2 ; ?,第7章 运算符重载,定义 运算符重载函数,第7章 运算符重载,7.1 运算符重载规则,7.2 用成员或友元函数重载运算符,7.3 几个典型运算符重载,7.4

2、 类类型转换,小结,7.1 运算符重载规则,7.1.1 重载运算符的限制,可以重载的运算符 +-*/% class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter

3、 = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter = Counter() ; ,void Calculator:operator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,例7-1 设计一个安全计数器,7.1.2 运算符重载的语法形式,#include #include using nam

4、espace std; class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i +

5、) - Counter; cout n Counter = Counter() ; ,void Calculator:operator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,重载了 3个运算符,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,#include #include using namespace std; class Calculator p

6、ublic: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter =

7、Counter() ; ,void Calculator:operator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,重载了 3个运算符,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,#include #include using namespace std; class Calculator public: Calculator() value = 0

8、; ; void operator + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter = Counter() ; ,void Calculator:o

9、perator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,void Calculator : operator + () if ( value 65535 ) value + ; else cout nData overflow ! endl ; exit( 0 ) ; ,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,#include #include u

10、sing namespace std; class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i =

11、5 ; i + ) - Counter; cout n Counter = Counter() ; ,void Calculator:operator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,void Calculator : operator + () if ( value 65535 ) value + ; else cout nData overflow ! end

12、l ; exit( 0 ) ; ,使用 系统预定义版本,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,#include #include using namespace std; class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for

13、( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter = Counter() ; ,void Calculator:operator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,void Calcula

14、tor : operator - () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; ,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,#include #include using namespace std; class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned short operator() () ; private: un

15、signed short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter = Counter() ; ,void Calculator:operator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; uns

16、igned short Calculator:operator() () return value ; ,void Calculator : operator - () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; ,使用 系统预定义版本,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,#include #include using namespace std; class Calculator public: Calculator() value = 0 ; ; void ope

17、rator + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter = Counter() ; ,void Calculator:operator + ()

18、 if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,+ Counter;,调用重载版本,void operator + () ;,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,#include #include using namespace std; class Calculator public: Calculator() value = 0 ; ; void oper

19、ator + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter = Counter() ; ,void Calculator:operator + ()

20、if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,调用重载版本,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,+ Counter;,void operator + () ;,#include #include using namespace std; class Calculator public: Calculator() value = 0 ; ; void opera

21、tor + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter = Counter() ; ,void Calculator:operator + () i

22、f ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,调用重载版本,Counter.operator+() ；,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,void operator + () ;,#include #include using namespace std; class Calculator public: Calculator() value = 0 ; ;

23、void operator + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter = Counter() ; ,void Calculator:opera

24、tor + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,- Counter;,调用重载版本,void operator - () ;,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,#include #include using namespace std; class Calculator public: Calculator() value = 0 ; ; v

25、oid operator + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter = Counter() ; ,void Calculator:operat

26、or + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,调用重载版本,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,- Counter;,void operator - () ;,#include #include using namespace std; class Calculator public: Calculator() value = 0 ; ; vo

27、id operator + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter = Counter() ; ,void Calculator:operato

28、r + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,调用重载版本,Counter.operator-() ；,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,void operator - () ;,#include #include using namespace std; class Calculator public: Calculator() value

29、= 0 ; ; void operator + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter = Counter() ; ,void Calculat

30、or:operator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,Counter () ;,调用重载版本,unsigned short operator () () ;,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,#include #include using namespace std; class Calculator public: Calcula

31、tor() value = 0 ; ; void operator + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter = Counter() ; ,v

32、oid Calculator:operator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,Counter () ;,unsigned short operator () () ;,被重载的运算符,#include #include using namespace std; class Calculator pu

33、blic: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned int operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter = Cou

34、nter() ; ,void Calculator:operator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned short Calculator:operator() () return value ; ,Counter () ;,Counter. operator() () ；,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,unsigned short operator () () ;,函数参数表,#include #include using

35、namespace std; class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned short operator() () ; private: unsigned short value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i

36、 + ) - Counter; cout n Counter = Counter() ; ,void Calculator:operator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; Unsigned short Calculator:operator() () return value ; ,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,#include #include using namespace std; class Calculator public:

37、Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned int operator() () ; private: unsigned int value; ; int main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter; cout n Counter = Counter() ;

38、 ,void Calculator:operator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; exit( 0 ) ; unsigned int Calculator:operator() () return value ; ,7.1.2 运算符重载的语法形式,例7-1 设计一个安全计数器,运算符函数可以重载为成员函数或友元函数 关键区别在于成员函数具有 this 指针，友元函数没有this指针 不管是成员函数还是友元函数重载，运算符的使用方法相同。 但传递参数的方式不同，实现代码不同，应用场合也不同,7.

39、2 用成员或友元函数重载运算符,重载为成员函数，解释为： Object . operator op () 操作数由对象Object通过this指针隐含传递 重载为友元函数，解释为： operator op (Object) 操作数由参数表的参数Object提供,7.2 用成员或友元函数重载运算符,1一元运算符,Object op 或 op Object,重载为成员函数，解释为： ObjectL . operator op ( ObjectR ) 左操作数由ObjectL通过this指针传递，右操作数由参数ObjectR传递 重载为友元函数，解释为： operator op ( ObjectL,

40、 ObjectR ) 左右操作数都由参数传递,7.2 用成员或友元函数重载运算符,2二元运算符,ObjectL op ObjectR,当一元运算符的操作数，或者二元运算符的左操作数 是类的对象时，定义重载运算符函数为成员函数,7.2.1 用成员函数重载运算符,例7-2 建立一个描述3维坐标的类 Tri_Coor，重载运算符 “+”、“+”、和 “=” ，实现简单的算术运算,7.2.1 用成员函数重载运算符,7.2.1 用成员函数重载算符,7.2.1 用成员函数重载算符,#include using namespace std; class TriCoor public: TriCoor( in

41、t mx = 0, int my = 0, int mz = 0 ) x = mx ; y = my ; z = mz ; TriCoor operator + ( TriCoor t ) TriCoor temp ; temp.x = x+t.x ; temp.y = y+t.y ; temp.z = z+t.z ; return temp ; TriCoor operator = ( TriCoor t ) x = t.x ; y = t.y ; z = t.z ; return * this ; TriCoor operator + () x + ; y + ; z + ; return

42、 *this ; void show() cout x , y , z n; void assign( int mx, int my, int mz ) x = mx; y = my; z = mz; private: int x, y, z ;/ 3_d coordinates ; int main() TriCoor a( 1, 2, 3 ), b, c ; a.show(); b.show(); c.show(); for( int i = 0; i 5; i + ) + b; b.show() ; c.assign( 3, 3, 3 ) ; c = a + b + c ; c.show

43、() ; c = b = a ; c.show() ; ,例7-2,#include using namespace std; class TriCoor public: TriCoor( int mx = 0, int my = 0, int mz = 0 ) x = mx ; y = my ; z = mz ; TriCoor operator + ( TriCoor t ) TriCoor temp ; temp.x = x+t.x ; temp.y = y+t.y ; temp.z = z+t.z ; return temp ; TriCoor operator = ( TriCoor

44、 t ) x = t.x ; y = t.y ; z = t.z ; return * this ; TriCoor operator + () x + ; y + ; z + ; return *this ; void show() cout x , y , z n; void assign( int mx, int my, int mz ) x = mx; y = my; z = mz; private: int x, y, z ;/ 3_d coordinates ; int main() TriCoor a( 1, 2, 3 ), b, c ; a.show(); b.show();

45、c.show(); for( int i = 0; i 5; i + ) + b; b.show() ; c.assign( 3, 3, 3 ) ; c = a + b + c ; c.show() ; c = b = a ; c.show() ; ,TriCoor operator + ( TriCoor t ) TriCoor temp ; temp.x = this-x+t.x ; temp.y = this-y+t.y ; temp.z = this-z+t.z ; return temp ; ,c = a + b + c ;,a + b a.operator + (b), Objec

46、t1,通过匿名对象Object1 返回运算结果,7.2.1 用成员函数重载算符,例7-2,7.2.1 用成员函数重载算符,#include using namespace std; class TriCoor public: TriCoor( int mx = 0, int my = 0, int mz = 0 ) x = mx ; y = my ; z = mz ; TriCoor operator + ( TriCoor t ) TriCoor temp ; temp.x = x+t.x ; temp.y = y+t.y ; temp.z = z+t.z ; return temp ; T

47、riCoor operator = ( TriCoor t ) x = t.x ; y = t.y ; z = t.z ; return * this ; TriCoor operator + () x + ; y + ; z + ; return *this ; void show() cout x , y , z n; void assign( int mx, int my, int mz ) x = mx; y = my; z = mz; private: int x, y, z ;/ 3_d coordinates ; int main() TriCoor a( 1, 2, 3 ),

48、b, c ; a.show(); b.show(); c.show(); for( int i = 0; i 5; i + ) + b; b.show() ; c.assign( 3, 3, 3 ) ; c = a + b + c ; c.show() ; c = b = a ; c.show() ; ,TriCoor operator + ( TriCoor t ) TriCoor temp ; temp.x = this-x+t.x ; temp.y = this-y+t.y ; temp.z = this-z+t.z ; return temp ; ,c = a + b + c ;,a

49、+ b a.operator + (b), Object1, a + b + c Object1 + c Object1.operator + (c),通过匿名对象Object2 返回运算结果, Object2,例7-2,#include using namespace std; class TriCoor public: TriCoor( int mx = 0, int my = 0, int mz = 0 ) x = mx ; y = my ; z = mz ; TriCoor operator + ( TriCoor t ) TriCoor temp ; temp.x = x+t.x ;

50、 temp.y = y+t.y ; temp.z = z+t.z ; return temp ; TriCoor operator = ( TriCoor t ) x = t.x ; y = t.y ; z = t.z ; return * this ; TriCoor operator + () x + ; y + ; z + ; return *this ; void show() cout x , y , z n; void assign( int mx, int my, int mz ) x = mx; y = my; z = mz; private: int x, y, z ;/ 3

51、_d coordinates ; int main() TriCoor a( 1, 2, 3 ), b, c ; a.show(); b.show(); c.show(); for( int i = 0; i 5; i + ) + b; b.show() ; c.assign( 3, 3, 3 ) ; c = a + b + c ; c.show() ; c = b = a ; c.show() ; ,TriCoor operator + ( TriCoor t ) TriCoor temp ; temp.x = this-x+t.x ; temp.y = this-y+t.y ; temp.

52、z = this-z+t.z ; return temp ; ,c = a + b + c ;,a + b a.operator + (b), Object1, a + b + c Object1 + c Object1.operator + (c), Object2, c = a + b + c ; c = Object2 ;,7.2.1 用成员函数重载算符,例7-2,#include using namespace std; class TriCoor public: TriCoor( int mx = 0, int my = 0, int mz = 0 ) x = mx ; y = my

53、 ; z = mz ; TriCoor operator + ( TriCoor t ) TriCoor temp ; temp.x = x+t.x ; temp.y = y+t.y ; temp.z = z+t.z ; return temp ; TriCoor operator = ( TriCoor t ) x = t.x ; y = t.y ; z = t.z ; return * this ; TriCoor operator + () x + ; y + ; z + ; return *this ; void show() cout x , y , z n; void assign

54、( int mx, int my, int mz ) x = mx; y = my; z = mz; private: int x, y, z ;/ 3_d coordinates ; int main() TriCoor a( 1, 2, 3 ), b, c ; a.show(); b.show(); c.show(); for( int i = 0; i 5; i + ) + b; b.show() ; c.assign( 3, 3, 3 ) ; c = a + b + c ; c.show() ; c = b = a ; c.show() ; ,TriCoor operator = (

55、TriCoor t ) this-x = t.x ; this-y = t.y ; this-z = t.z ; return * this ; ,c = b = a ;,b = a b.operator = (a), c = b c.operator = (b),返回调用函数的对象,7.2.1 用成员函数重载算符,例7-2,#include using namespace std; class TriCoor public: TriCoor( int mx = 0, int my = 0, int mz = 0 ) x = mx ; y = my ; z = mz ; TriCoor operator + ( TriCoor t ) TriCoor temp ; temp.x = x+t.x ; temp.y = y+t.y ; temp.z = z+t.z ; return temp ; TriCoor operator = ( TriCoor t ) x = t.x ; y = t.y ; z = t.z ; return *