Ⅴ运算符重载

#include
using namespace std;
class Complex
{
float real, imag; //实部和虚部
public:
Complex(float r=0,float i=0)
{
real = r;
imag = i;
}
Complex operator+(Complex other) //+运算符的重载
{
Complex r;
r.real = real + other.real;
r.imag = imag + other.imag;
return r;
}
void Output()
{
if(imag>0)
cout <"+" <"i" << endl;
else
cout <"i" << endl;
}
};
int main()
{
Complex a(2,3), b(3, 4), c;
c = a + b;
c.Output();
return 0;
}

class Complex
{
public:
Complex(double=0.0,double=0.0);//constructor
Complexoperator+(const Complex &);//addition
private:
double real; //real part
double imaginary;//imaginary part
};
Complex Complex::operator+(const Complex &operand2)
{
return Complex(real+operand2.real, imaginary+operand2.imaginary);
}

Complex Complex::operator=(Complex c2)
{
real = c2.real;
imag = c2.imag;
return *this; //指针的使用
}

// Overload postfix ++ for Complex.
Complex Complex::operator++(int x) //后缀的话要传入一个参数加以区分
{
Complex r = *this; //要新建一个指针
real++;
imag++;
return r;
}
// Overload prefix ++ for Complex.
Complex Complex::operator++() //前缀的话就是普通的，默认是前缀的
{
++real;
++imag;
return *this; //直接返回就行
}
int main()
{
Complex a(2,3), b(3, 4), c;
c = a * b;
Complex d = ++c; //但是可以看到在使用的时候没有区别
Complex e = d++; //后缀并不需要传递那个int
d.Output();
e.Output();
return 0;
}

friend Complex operator+(float x, Complex c)
{
Complex r;
r.real = x+c.real;
r.imag = c.imag;
return r;
}

class Complex {
public:
　　Complex( double r = 0.0, double i= 0.0 ){
　　　　real = r;
　　　　imaginary = i;
}
　　double real;       // real part
　　double imaginary;  // imaginary part
};

Complex operator+( const Complex & a ,const Complex & b)
{
return Complex( a.real+b.real,a.imaginary+b.imaginary);
}
Complex a(1,2), b(2,3),c;
// “类名（参数表）”就代表个对象
c = a + b; // 等效于c = operator+(a,b);
重载为普通函数时，参数个数为运算符目数
注意：类的成员变量要为public(故用得少)

int main()
{
Complex a, b, c;
cin >> a >> b; //实现直接输入输出
c = a * b;
Complex d = ++c;
Complex e = d++;
d = d+1.01;
e = 1.01+e;
cout < e;
return 0;
}
friend istream &operator>>(istream &in, Complex &c)//因为要改变值所以有引用
{
in >> c.real >> c.imag;
return in;
}
friend ostream &operator<<(ostream &out, Complex c)
{
if(c.imag>0)
out <"+" <"i" << endl;
else
out <"i" << endl;
return out;
}

float &Complex::operator[](int i) //要修改时，就要用引用
{
if (i==0) //实部是啥
return real;
else if(i==1)
return imag;
else
{
cout <<"Out of boundary" << endl;
exit(1);
}
}
int main()
{
Complex c(3, 4);
cout <0] <//输出实部
c[1] = 5;
cout << c;
c[2] = 6; //一共就俩数，超了
}