第一种重载方式：
Complex operator + (Complex & c2)
{
Complex c;
return c; //此处返回局部变量c；
}
第二种重载方式：
Complex & operetor + (Complex)
{
this->i=this->i+c2.i;
this->j=this->i+c2.j;
return *this; //此处返回this
}
实例：
#include<iostream>
using namespace std;
class Complex
{
public:
double i;
double j;
Complex ()
{
this->i=0;
this->j=0;
}
Complex(double i,double j)
{
this->i=i;
this->j=j;
}
void show()
{
cout<<"this->i="<<this->i<<endl<<"this->j="<<this->j<<endl;
}
/*
Complex & operator + (const Complex &c2)
{
this->i=this->i + c2.i;
this->j=this->j + c2.j;
return *this;
}
*/
Complex operator + (Complex &c2)
{
Complex c;
c.i=this->i+c2.i;
c.j=this->j+c2.j;
return c;
}
};
void f1()
{
Complex c1(1.1,3.3);
Complex c2(2.2,4.4);
Complex c3=c1+c2;
c3.show();
}
int main()
{
f1();
return 0;
}
farsight@ubuntu:~/shell$
farsight@ubuntu:~/shell$ ./a.out
this->i=3.3
this->j=7.7
farsight@ubuntu:~/shell$
实例2：
#include<iostream>
using namespace std;
class Complex
{
public:
double i;
double j;
Complex ()
{
this->i=0;
this->j=0;
}
Complex(double i,double j)
{
this->i=i;
this->j=j;
}
void show()
{
cout<<"this->i="<<this->i<<endl<<"this->j="<<this->j<<endl;
}
Complex & operator + (const Complex &c2)
{
this->i=this->i + c2.i;
this->j=this->j + c2.j;
return *this;
}
/*
Complex operator + (Complex &c2)
{
Complex c;
c.i=this->i+c2.i;
c.j=this->j+c2.j;
return c;
}
*/
};
void f1()
{
Complex c1(1.1,3.3);
Complex c2(2.2,4.4);
Complex c3=c1+c2;
c3.show();
}
int main()
{
f1();
return 0;
}
farsight@ubuntu:~/shell$ vi complex.cpp
farsight@ubuntu:~/shell$ vi complex.cpp
farsight@ubuntu:~/shell$ ./a.out
this->i=3.3
this->j=7.7
farsight@ubuntu:~/shell$
还有一个疑问：
Complex & operator+（Complex &c2） 这种重载方式可以加拷贝构造函数，但是打印结果又错。
#include<iostream>
using namespace std;
class Complex
{
public:
double i;
double j;
Complex ()
{
this->i=0;
this->j=0;
}
Complex(Complex &zhang)
{
cout<<"copy"<<endl;
}
Complex(double i,double j)
{
this->i=i;
this->j=j;
}
void show()
{
cout<<"this->i="<<this->i<<endl<<"this->j="<<this->j<<endl;
}
Complex & operator + (const Complex &c2)
{
this->i=this->i + c2.i;
this->j=this->j + c2.j;
return *this;
}
/*
Complex operator + (Complex &c2)
{
Complex c;
c.i=this->i+c2.i;
c.j=this->j+c2.j;
return c;
}
*/
};
void f1()
{
Complex c1(1.1,3.3);
Complex c2(2.2,4.4);
Complex c3=c1+c2;
c3.show();
}
int main()
{
f1();
return 0;
}
farsight@ubuntu:~/shell$
farsight@ubuntu:~/shell$ ./a.out
copy
this->i=-0.0982316 //结果有错，不知道为什么？
this->j=-3.46551e-42
farsight@ubuntu:~/shell$