c++运算符重载经典举例.doc

c+运算符重载经典举例算法运算符重载/ A class Complex, and its arithmetic operations.#include #include #include class Complexpublic: Complex( float r = 0, float i = 0 ) : _r( r ), _i( i ) void print( ) const; friend const Complex operator+(const Complex& x, const Complex& y); friend const Complex operator-(const Complex& x, const Complex& y); friend const Complex operator*(const Complex& x, const Complex& y); friend const Complex operator/(const Complex& x, const Complex& y);private: float _r; float _i;void Complex:print( ) const cout_r = _rendl; cout_I = _iendl;inline const Complex operator+(const Complex& x, const Complex& y) return Complex( x._r + y._r, x._i + y._i);inline const Complex operator-(const Complex& x, const Complex& y) return Complex(x._r - y._r, x._i - y._i);inline const Complex operator*(const Complex& x, const Complex& y) return Complex( x._r * y._r - x._i * y._i, x._r * y._i + x._i * y._r);const Complex operator/(const Complex& x, const Complex& y) if (y._r = 0 & y._i = 0) exit(1); float den = y._r * y._r + y._i * y._i; Complex aComplex(x._r * y._r + x._i * y._i) / den, (x._i * y._r - x._r * y._i) / den); /return Complex(x._r * y._r + x._i * y._i) / den, / (x._i * y._r - x._r * y._i) / den); return aComplex;int main( ) Complex x(2, 3), y(-1, 3); cout x is ; x.print( ); cout y is ; y.print( ); cout x + y is ; (x + y).print( ); cout x - y is ; (x - y).print( ); cout x * y is ; (x * y).print( ); cout x / y is ; (x / y).print( ); return 0;引用 报告 回复 sdb 新手上路UID 1050精华 0积分 0帖子 24阅读权限 10注册 2007-4-2状态 离线 #2使用道具发表于 2007-7-11 14:52 资料 个人空间 短消息 加为好友 重载为成员函数/ A class Complex, and its arithmetic operations.#include #include #include class Complexpublic: Complex( float r = 0, float i = 0 ) : _r( r ), _i( i ) void print( ) const; const Complex operator+(const Complex& y); const Complex operator-(const Complex& y); const Complex operator*(const Complex& y); const Complex operator/(const Complex& y);private: float _r; float _i;void Complex:print( ) const cout_r = _rendl; cout_I = _iendl;inline const Complex Complex:opearator+(const Complex& y) return Complex( _r + y._r, _i + y._i);inline const Complex Complex:operator-(const Complex& y) return Complex(_r - y._r, _i - y._i);inline const Complex Complex:operator*(const Complex& y) return Complex( _r * y._r - _i * y._i, _r * y._i + _i * y._r);const Complex Complex:operator/(const Complex& y) if (y._r = 0 & y._i = 0) exit(1); float den = y._r * y._r + y._i * y._i; Complex aComplex(_r * y._r + _i * y._i) / den, (_i * y._r - _r * y._i) / den); /return Complex(x._r * y._r + x._i * y._i) / den, / (x._i * y._r - x._r * y._i) / den); return aComplex;int main( ) Complex x(2, 3), y(-1, 3); cout x is ; x.print( ); cout y is ; y.print( ); cout x + y is ; (x + y).print( ); cout x - y is ; (x - y).print( ); cout x * y is ; (x * y).print( ); cout x / y is ; (x / y).print( ); return 0; 本帖最后由 sdb 于 2007-7-11 14:58 编辑 引用 报告 回复 sdb 新手上路UID 1050精华 0积分 0帖子 24阅读权限 10注册 2007-4-2状态 离线 #3使用道具发表于 2007-7-11 14:53 资料 个人空间 短消息 加为好友 重载下标操作符/ Class Vector is to demonstrator overloading the subscript operator#include #define size 5class Vectorprivate: int repsize;public: const int& operator (int index) const return repindex; int& operator (int index) return repindex; ;/ Using the overloaded operator , this function does not access / the private member of class Vectorostream& operator(ostream& out, const Vector& a) for (int i = 0; i size; +i) out a endl; /outa.rep; / the const version of operator is used return out;int main( ) Vector x; cout Enter size integers.n; for (int i = 0; i x; / the non-const version of operator is used const Vector y = x; cout y = ; cout y; x0 = 1; / Non-const version again cout y = ; cout y; cout x = ; coutx; return 0;/ This example defines the second version of the class Vector, which has overloaded operators =, / and . #include class Vectorpublic: Vector(int s, int an_array ); / a constructor Vector( ) delete rep; / a destructor int get_size( ) const return size; / an accessor const Vector& operator=(const Vector& x); int& operator (int index) return repindex; const int& operator (int index) const return repindex; private: int *rep; int size;/ A constructor initializing the members of rep by the parameter an_arrayVector: Vector(int s, int an_array ) : size(s), rep( new ints ) for (int i = 0; i size; +i) rep = an_array; / Note that the initializer uses new ints to initialize rep, but not new intsize/ because the initializers may not be evaluated in the specified order.const Vector& Vector:operator=(const Vector& x) if( this != &x) size = x.size; delete rep; / clean up the old one. rep = new intsize; for (int i = 0; i size; +i) rep = x.rep; return *this;ostream& operator(ostream& out, const Vector& x) int s = x.get_size( ); for (int i = 0; i s; +i) out xendl; return out;int main() int array5 = 1, 2, 3, 4, 5 ; Vector v1( 5, array ); coutv1= v1endl; Vector v2 = v1; coutv2= v2endl; v14 = 100; coutv2= v2endl; return 0; 本帖最后由 sdb 于 2007-7-11 14:58 编辑 引用 报告 回复 sdb 新手上路UID 1050精华 0积分 0帖子 24阅读权限 10注册 2007-4-2状态 离线 #4使用道具发表于 2007-7-11 14:54 资料 个人空间 短消息 加为好友 输出符重载/ To illustrate the dangers of the default assignment with dynamic memory allocation.#include #include const int MAX_CHAR = 10; class Account friend ostream& operator strlen(title) ) delete title; title = NULL; title = new charstrlen(newname)+1; strcpy( title, newname ); else strcpy(title, newname); void changename(char* newname) strcpy( owner, newname ); Account () delete title; private: char* title; char ownerMAX_CHAR; float balance; ; ostream& operator (ostream& os, Account &b) os who: b.title b.owner how much=b.balancen; os endl; return os; void main() Account acc(Lou,Mr, 100); Account acc1; cout acc; cout acc1; acc1=acc; cout acc1; acc1.changename(jean); cout acc1; coutacc; acc1.changetitle(Dr.); cout acc1; coutacc;引用 报告 回复 sdb 新手上路UID 1050精华 0积分 0帖子 24阅读权限 10注册 2007-4-2状态 离线 #5使用道具发表于 2007-7-11 14:59 资料 个人空间 短消息 加为好友 容器的构造/ The following is another version of the class Vector with three constructors, a destructor (which / is the same as in the previous example), an overloaded assignment operator, an overloaded/ output operator, and an overloaded equality operator.#include class Vectorprivate: int *rep; int size; void clone(const Vector& a); void dispose( );public: Vector(int s=0); / a default constructor initializing all members of rep to 0 if s is not 0. Vector(int *, int); / a constructor creates a Vector object from an ordinary array Vector(const Vector& v); / a copy constructor Vector( ) dispose( ); / a destructor int get_size( ) const return size; / an accessor const Vector& operator=(const Vector& x); int& operator (int index) return repindex; const int& operator (int index) const return repindex;void Vector:clone(const Vector& a) this-size = a.size; rep = new intsize; for (int count = 0; count size; +count) repcount = acount;void Vector:dispose( ) delete rep; Vector:Vector(int s) : size(s) if (size = 0) rep = NULL; else rep = new intsize; for (int count = 0; count size; +count) repcount = 0; Vector:Vector(int * a, int s) : size(s), rep(new ints) for (int count = 0; count size = a.size; rep = new intsize; for (int count = 0; count size; +count) repcount = acount; return *this;/ overloading operator , not a friend functionostream& operator(ostream& out, const Vector& x) int s = x.get_size( ); for (int i = 0; i s; +i) out xendl; out endl; return out;bool operator=(const Vector& a, const Vector& b) bool yes = true; if (a.get_size( ) != b.get_size( ) yes = false; else int s, index = 0; s = a.get_size( ); while (index s & aindex = bindex) +index; if (index s) yes = false; return yes;引用 报告 回复 sdb 新手上路UID 1050精华 0积分 0帖子 24阅读权限 10注册 2007-4-2状态 离线 #6使用道具发表于 2007-7-11 15:01 资料 个人空间 短消息 加为好友 类型转换/ The following example demonstrates when a constructor or a destructor is called:#include class Demoprivate: int i;public: / default constructor Demo(int n = 0) : i(n) cout default constructor calledn; / copy constructor: for example Demo b(a); Demo(const Demo& a) i = a.i;cout copy constructor calledn; / destructor Demo( ) cout i = a.i; cout assignment operator usedn; return *this; Demo& set_value(int n) i = n; return *this; / returning an object to facilitate function chain int get_value( ) return i;Demo foo(Demo x)/ pass by value to invoke copy constructor Demo d; return d; / returning a local object by value int main( ) Demo a(2); Demo b; b = foo(a); Demo c = a; return 0;引用 报告 回复 sdb 新手上路UID 1050精华 0积分 0帖子 24阅读权限 10注册 2007-4-2状态 离线 #7使用道具发表于 2007-7-11 15:02 资料 个人空间 短消息 加为好友 字符串的构造/ Constructor type conversion#include #include class String int len; char * rep;public: String( ) : len(0) / default constructor rep = new char1; strcpy(rep, ); String(char * s) / another constructor if (!s) len = 0; s = new char1; strcpy(rep, ); else len = strlen(s); rep = new charlen + 1; strcpy(rep, s); String(const String& str) : len(str.len), rep(new charstr.len + 1) / copy constructor strcpy(rep, str.rep); String( ) / destructor delete rep; friend void print(const String& s);void print(const String& s) cout s.rep ; return;int main( ) char * a = first string; print(a); print(second string); String b = bad initialization; print(b); return 0;引用 报告 回复 sdb 新手上路UID 1050精华 0积分 0帖子 24阅读权限 10注册 2007-4-2状态 离线 #8使用道具发表于 2007-7-11 15:04 资料 个人空间 短消息 加为好友 / The following program defines four arrays of objects in class Item.The first array initializes the / objects by calling the constructor explicitly.The second