1、運算符重載使得用戶自定義的數(shù)據(jù)以一種更簡潔的方式工作,例如 int x , y; y = x + y ;,matrix m1 , m2 ;/ 矩陣類對象 m2 = Madd ( m1 , m2 ) ;/ 調用函數(shù)計算兩個矩陣的和,complex c1 , c2 ; / 復數(shù)類對象 c1 = Cadd (c1 , c2 ) ;/ 調用函數(shù)計算兩個復數(shù)的和,能表示為 c1 = c1 + c2 ; ?,能表示為 m1 = m1 + m2 ; ?,第6章 運算符重載,定義 運算符重載函數(shù),第6章 運算符重載,6.1 運算符重載規(guī)則,6.2 用成員或友員函數(shù)重載運算符,6.3 幾個典型運算符重載,6.4

2、 類類型轉換,小結,6.1 運算符重載規(guī)則,6.1.1 重載運算符的限制,可以重載的運算符 +-*/% ; void operator + () ; void operator - () ; unsigned int operator() () ; private: unsigned int value; ; void main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) + Counter; cout n Counter = Counter() ; for( i = 0 ; i = 5 ; i + ) - Counter;

3、cout n Counter = Counter() ; ,void Calculator:operator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; abort() ; unsigned int Calculator:operator() () return value ; ,例6-1 設計一個安全計數(shù)器,6.1.2 運算符重載的語法形式,#include #include class Calculator public: Calculator() value = 0 ; ; void operator

4、+ () ; void operator - () ; unsigned int operator() () ; private: unsigned int value; ; void 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 ( val

5、ue 0 ) value - ; else cout n Data overflow ! endl ; abort() ; unsigned int Calculator:operator() () return value ; ,重載了 3個算符,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned int operator() () ; pr

6、ivate: unsigned int value; ; void 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 ; abort()

7、 ; unsigned int Calculator:operator() () return value ; ,重載了 3個算符,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned int operator() () ; private: unsigned int value; ; void main() Calculator Counter

8、 ; 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 ; abort() ; unsigned int Calculator:operator() () return value ; ,vo

9、id Calculator : operator + () if ( value 65535 ) value + ; else cout nData overflow ! endl ; abort() ; ,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned int operator() () ; private: unsigned int v

10、alue; ; void 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 ; abort() ; unsigned int Calcu

11、lator:operator() () return value ; ,void Calculator : operator + () if ( value 65535 ) value + ; else cout nData overflow ! endl ; abort() ; ,使用 系統(tǒng)預定義版本,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; uns

12、igned int operator() () ; private: unsigned int value; ; void 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 Da

13、ta overflow ! endl ; abort() ; unsigned int Calculator:operator() () return value ; ,void Calculator : operator - () if ( value 0 ) value - ; else cout n Data overflow ! endl ; abort() ; ,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value = 0 ; ; void opera

14、tor + () ; void operator - () ; unsigned int operator() () ; private: unsigned int value; ; void 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 (

15、 value 0 ) value - ; else cout n Data overflow ! endl ; abort() ; unsigned int Calculator:operator() () return value ; ,void Calculator : operator - () if ( value 0 ) value - ; else cout n Data overflow ! endl ; abort() ; ,使用 系統(tǒng)預定義版本,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator

16、 public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned int operator() () ; private: unsigned int value; ; void 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 = C

17、ounter() ; ,void Calculator:operator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; abort() ; unsigned int Calculator:operator() () return value ; ,+ Counter;,調用重載版本,void operator + () ;,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value =

18、 0 ; ; void operator + () ; void operator - () ; unsigned int operator() () ; private: unsigned int value; ; void 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

19、perator + () if ( value 0 ) value - ; else cout n Data overflow ! endl ; abort() ; unsigned int Calculator:operator() () return value ; ,+ Counter;,void operator + () ;,調用重載版本,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value = 0 ; ; void operator + () ; v

20、oid operator - () ; unsigned int operator() () ; private: unsigned int value; ; void 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 ) v

21、alue - ; else cout n Data overflow ! endl ; abort() ; unsigned int Calculator:operator() () return value ; ,void operator + () ;,調用重載版本,Counter.operator+() ；,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - ()

22、; unsigned int operator() () ; private: unsigned int value; ; void 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

23、 n Data overflow ! endl ; abort() ; unsigned int Calculator:operator() () return value ; ,- Counter;,調用重載版本,void operator - () ;,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned int operator() ()

24、; private: unsigned int value; ; void 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 ; abo

25、rt() ; unsigned int Calculator:operator() () return value ; ,- Counter;,調用重載版本,void operator - () ;,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned int operator() () ; private: unsigned int value

26、; ; void 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 ; abort() ; unsigned int Calculato

27、r:operator() () return value ; ,調用重載版本,void operator - () ;,Counter.operator-() ；,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned int operator() () ; private: unsigned int value; ; void main() Ca

28、lculator 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 ; abort() ; unsigned int Calculator:operator() () re

29、turn value ; ,Counter () ;,調用重載版本,void operator () () ;,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned int operator() () ; private: unsigned int value; ; void main() Calculator Counter ; int i ;

30、 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 ; abort() ; unsigned int Calculator:operator() () return value ; ,Counter () ;

31、,void operator () () ;,被重載的運算符,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned int operator() () ; private: unsigned int value; ; void main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + )

32、 + 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 ; abort() ; unsigned int Calculator:operator() () return value ; ,Counter () ;,void operator () () ;,函數(shù)

33、參數(shù)表,Counter. operator() () ；,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned int operator() () ; private: unsigned int value; ; void main() Calculator Counter ; int i ; for( i = 0 ; i 5 ; i + ) +

34、 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 ; abort() ; unsigned int Calculator:operator() () return value ; ,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#includ

35、e #include class Calculator public: Calculator() value = 0 ; ; void operator + () ; void operator - () ; unsigned int operator() () ; private: unsigned int value; ; void 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 ; abort() ; unsigned int Calculator:operator() () return value ; ,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,#include #include class Calculator public: Calculator() value = 0 ; ; void

37、operator + () ; void operator - () ; unsigned int operator() () ; private: unsigned int value; ; void 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 + ()

38、 if ( value 0 ) value - ; else cout n Data overflow ! endl ; abort() ; unsigned int Calculator:operator() () return value ; ,6.1.2 運算符重載的語法形式,例6-1 設計一個安全計數(shù)器,運算符函數(shù)可以重載為成員函數(shù)或友員函數(shù) 關鍵區(qū)別在于成員函數(shù)具有 this 指針，友員函數(shù)沒有this指針 不管是成員函數(shù)還是友員函數(shù)重載，算符的使用方法相同。但 傳遞參數(shù)的方法不同，實現(xiàn)代碼不同，應用場合也不同,6.2 用成員或友員函數(shù)重載運算符,重載為成員函數(shù)，解釋為： Objec

39、t . operator op () 操作數(shù)由對象Object通過this指針隱含傳遞 重載為友員函數(shù)，解釋為： operator op (Object) 操作數(shù)由參數(shù)表的參數(shù)Object提供,6.2 用成員或友員函數(shù)重載運算符,1一元運算符,Object op 或 op Object,重載為成員函數(shù)，解釋為： ObjectL . operator op ( ObjectR ) 左操作數(shù)由ObjectL通過this指針傳遞，右操作數(shù)由參數(shù)ObjectR傳遞 重載為友員函數(shù)，解釋為： operator op ( ObjectL, ObjectR ) 左右操作數(shù)都由參數(shù)傳遞,6.2 用成員或友員函

40、數(shù)重載運算符,2二元運算符,ObjectL op ObjectR,當一元運算符的操作數(shù)，或者二元運算符的左操作數(shù) 是該類的一個對象時，定義重載算符函數(shù)為成員函數(shù),6.2.1 用成員函數(shù)重載算符,6.2.1 用成員函數(shù)重載算符,例6-2 建立一個描述3維坐標的類 Tri_Coordinates，重載算符 “+”、“+”、和 “=” ，實現(xiàn)簡單的算術運算,6.2.1 用成員函數(shù)重載算符,6.2.1 用成員函數(shù)重載算符,#include class TriCoor public: TriCoor( int mx = 0, int my = 0, int mz = 0 ) x = mx ; y = m

41、y ; 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 assig

42、n( int mx, int my, int mz ) x = mx; y = my; z = mz; private: int x, y, z ;/ 3_d coordinates ; void 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() ; ,6.2.1 用成員函數(shù)重載算符,例6-

43、2,#include 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 * this ; Tr

44、iCoor 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 ; void main() TriCoor a( 1, 2, 3 ), b, c ; a.show(); b.show(); c.show(); for( int i = 0; i 5; i + ) + b; b.show() ;

45、 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-x+t.z ; return temp ; ,c = a + b + c ;,a + b a.operator + (b), Object1,通過匿名對象Object1 返回運算結果,6.2.1 用成員函數(shù)重載算符,例6-2,#includ

46、e 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 * this ; TriCoor ope

47、rator + () 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 ; void 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

48、( 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-x+t.z ; return temp ; ,c = a + b + c ;,a + b a.operator + (b), Object1, a + b + c Object1 + c Object1.operator + (c),通過匿名對象Object

49、2 返回運算結果, Object2,6.2.1 用成員函數(shù)重載算符,例6-2,#include 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

50、 = 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 ; void main() TriCoor a( 1, 2, 3 ), b, c ; a.show(); b.show(); c.show(); for(

51、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-x+t.z ; return temp ; ,c = a + b + c ;,a + b a.operator + (b), Object1, a + b + c O

52、bject1 + c Object1.operator + (c), Object2, c = a + b + c ; c = Object2 ;,6.2.1 用成員函數(shù)重載算符,例6-2,#include 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 ; re

53、turn 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_d coordinates ; void main() TriCoor

54、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 ) this-x = t.x ; this-y = t.y ; this-z = t.z ; return * this ; ,c = b = a ;,b = a b.operator = (a), c

55、= b c.operator = (b),返回調用函數(shù)的對象,6.2.1 用成員函數(shù)重載算符,例6-2,#include 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 * this ; TriCoor operator + () x + ; y + ; z + ; return *this ; void show() cout x ,