Operator overloading in C + +

Four types of operators that cannot be overloaded:

1>:: domain operator

2>. Member access operators

3> * Member pointer access operator ((*this). Member)

4>:? Trinocular operator

Operators that can only be overloaded with a tuple:

1> << output operator overloading

2> >> input operator overloading

An operator overload that declares a friend and can be declared as a member function of a class:

1> arithmetic character

2> + +--operator

3> = = = = = *=/= operator

Operators that can only be declared as member functions of a class

1>[] Subscript operator

2> ()

3>

4>= assignment operator

Operators that are generally not overloaded

1>=

2>&

3>*

In addition, overloads can only be existing operators, and the precedence of operators cannot be changed after overloading.

Here is an example:

  complex.h//  train5////  created by student on 15/8/ 11.//  copyright  (c)  2015 year  personals. all rights reserved.//#ifndef  __train5__complex__#define __train5__complex__#include <iostream>using namespace  std;class complex{public:    complex (int r1=0,int i1=0);     ~complex () {}    const complex& operator--();          //Pre-reduction (real part minus one, imaginary part unchanged)     const Complex  operator--(int);        //Reduction         reduction  friend const complex operator+ (const complex& p1,const complex& &NBSP;P2);     friend const complex operator-(const Complex&  P1,CONST&NBSP;COMPLEX&AMP;&NBSP;P2);     friend const complex operator* (Const complex& p1,const &NBSP;COMPLEX&AMP;&NBSP;P2);     friend const complex operator/(const  COMPLEX&AMP;&NBSP;P1,CONST&NBSP;COMPLEX&AMP;&NBSP;P2);    friend complex  operator+= (COMPLEX&AMP;&NBSP;C1,CONST&NBSP;COMPLEX&AMP;&NBSP;C2);     friend complex  operator-= (COMPLEX&AMP;&NBSP;C1,CONST&NBSP;COMPLEX&AMP;&NBSP;C2);    friend  Complex operator*= (COMPLEX&AMP;&NBSP;C1,CONST&NBSP;COMPLEX&AMP;&NBSP;C2);     friend  complex operator/= (COMPLEX&AMP;&NBSP;C1,CONST&NBSP;COMPLEX&AMP;&NBSP;C2);         friend ostream& operator<< (ostream& out,const  COMPLEX&AMP;&NBSP;C1);     friend bool operator== (const Complex& c1 , CONST&NBSP;COMPLEX&AMP;&NBSP;C2); &nbsP;   friend bool operator!= (const complex& c1,const complex& &NBSP;C2);    private:    int r,i;}; #endif  /* defined (__train5__complex__)  */

  complex.cpp//  train5////  created by student on 15/8/ 11.//  copyright  (c)  2015 year  personals. all rights reserved.//#include   "Complex.h" Complex::complex (INT&NBSP;R1,INT&NBSP;I1) {    r=r1;    &NBSP;I=I1;} const complex operator+ (CONST&NBSP;COMPLEX&AMP;&NBSP;P1,CONST&NBSP;COMPLEX&AMP;&NBSP;P2) {     return complex (p1.r+p2.r,p1.i+p2.i);} const complex operator-(CONST&NBSP;COMPLEX&AMP;&NBSP;P1,CONST&NBSP;COMPLEX&AMP;&NBSP;P2) {     return complex (p1.r-p2.r,p1.i-p2.i);} const complex operator* (CONST&NBSP;COMPLEX&AMP;&NBSP;P1,CONST&NBSP;COMPLEX&AMP;&NBSP;P2) {     return complex (P1.R*P2.R-P1.I*P2.I,P1.R*P2.I+P1.I*P2.R);} const complex operator/(CONST&NBSP;COMPLEX&AMP;&NBSP;P1,CONST&NBSP;COMPLEX&AMP;&NBSP;P2) {     float den=p2.r*p2.r+p2.i*p2.i;    return complex ((p1.r*p2.r+p1.i*p2.i)/den, (-P1.R*P2.I+P1.I*P2.R)/den);} complex operator+= (COMPLEX&AMP;&NBSP;C1,CONST&NBSP;COMPLEX&AMP;&NBSP;C2) {&NBSP;&NBSP;&NBSP;&NBSP;C1=C1+C2 ;     return c1;} complex operator-= (COMPLEX&AMP;&NBSP;C1,CONST&NBSP;COMPLEX&AMP;&NBSP;C2) {&NBSP;&NBSP;&NBSP;&NBSP;C1=C1-C2 ;     return c1;} Complex operator*= (COMPLEX&AMP;&NBSP;C1,CONST&NBSP;COMPLEX&AMP;&NBSP;C2) {&NBSP;&NBSP;&NBSP;&NBSP;C1=C1*C2 ;     return c1;} Complex operator/= (COMPLEX&AMP;&NBSP;C1,CONST&NBSP;COMPLEX&AMP;&NBSP;C2) {&NBSP;&NBSP;&NBSP;&NBSP;C1=C1/C2 ;     return c1;} /*const complex& complex::operator--() {    this->r-=1;     return *this;} *//*const complex complex::operator--(int) {    complex old =  (* this);     --(*this);    return old;} */const complex& complex::operator--() {    complex c (1,0);      (*this) = (*this)-c;    return *this;} const complex complex::operator--(int) {    complex old =  (*this);     complex c (1,0);     (*this) = (*this)-c;     Return old;} ostream& operator<< (OSTREAM&AMP;&NBSP;OUT,CONST&NBSP;COMPLEX&AMP;&NBSP;C1) {     out<< "r=" <<c1.r<< "i=" <<c1.i<<endl;    return out ;} bool operator== (CONST&NBSP;COMPLEX&AMP;&NBSP;C1,CONST&NBSP;COMPLEX&AMP;&NBSP;C2) {     if  (C1.R==C2.R  &&  (c1.i==c2.i))  {         return true;    }    else{     & NBsP;  return false;    }}bool operator!= (CONST&NBSP;COMPLEX&AMP;&NBSP;C1 , CONST&NBSP;COMPLEX&AMP;&NBSP;C2) {    if  ((C1.R==C2.R)  &&  (c1.i== C2.I))  {        return false;    }     else{        return true;     }}

  main.cpp//  train5////  created by student on 15/8/11.   Copyright  (c)  2015 year  personals. all rights reserved.//#include  <iostream> #include   "Complex.h" Int main (int argc, const char *  Argv[]) {&NBSP;&NBSP;&NBSP;&NBSP;//&NBSP;INSERT&NBSP;CODE&NBSP;HERE...&NBSP;&NBSP;&NBSP;&NBSP;COMPLEX&NBSP;C1 ( 1, 3), C2 (4,5);    complex c;    c1+=c2;     cout<<c1;    c1-=c2;    cout<<c1;     c1*=c2;    cout<<c1;    c1/=c2;    cout< <c1;    c1--;    --c1;    cout<<c1;     if  (C1==C2)  {        cout<< "c1==c2\n ";    &nBSP;}     else if  (C1!=C2) {        cout< < "c1!=c2\n";    }    //std::cout <<  "Hello,  World!\n ";     return 0;}

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Operator overloading in C + +