【c/c++】复数类
1.使用成员函数实现运算符的重载
#include<iostream>
using namespace std;
/*
1.同一个运算符可以代表多个不同的功能，编译系统是根据操作的数据来判别该执行具体哪一个功能的
*/class complex
{
public:complex(){ real = 0; imag = 0; } //有参和无参的构造函数complex(double r, double i){ real = r; imag = i; }//当运算符重载为类的成员函数时的时候，函数的参数的个数要比原来的操作数少一个（后置“++”、“-”除外），因为成员函数都是通过该类的某个对象来访问的，成员函数中有一隐含的参数this指针，this指针//指向当前的对象，而当前的对象本身就是其中的一个操作数。//当运算符重载为友元函数的时候，参数的个数与原来的操作数目是一样的complex operator+(complex &c2);//运算符的重载。因为本身的‘+’只能是对基本类型数据进行操作，现在想要对复数类也进行操作。那么必须要重载，重新定义其为我们需要的功能complex operator-(complex &c2);complex operator*(complex &c2);complex operator/(complex &c2);complex operator+(int &i);complex operator-(int &i);complex operator*(int &i);complex operator/(int &i);void display();
private:double real;double imag;
};
//不明白为什么这里的return不能像后面复数与整数相加时的return.
//解答：还不都是一样的，只不过是因为前面涉及到了实部和虚部操作，因此重新构造一个复数类的对象会使程序更加明了。
//后面只是用到了实部，因此不需要浪费内存空间，重新申请一个新的复数类的对象（乘除除外）。程序简化为直接创建一个临时的无名对象作为返回值，程序的运行效率更高//复数和复数的操作运算
complex complex::operator+(complex &c2)
{complex c;c.real = real + c2.real;c.imag = imag + c2.imag;return c;
}
complex complex::operator-(complex &c2)
{complex c;c.real = real - c2.real;c.imag = imag - c2.imag;return c;
}
complex complex::operator *(complex &c2)
{complex c;c.real = real*c2.real - imag*c2.imag;c.imag = imag*c2.real + real*c2.imag;return c;
}
complex complex::operator / (complex &c2)
{complex c;c.real = (real*c2.real + imag*c2.imag) / (c2.real*c2.real + c2.imag*c2.imag);c.imag = (imag*c2.real - real*c2.imag) / (c2.real*c2.real + c2.imag*c2.imag);return c;
}//复数与整数之间的操作
complex complex::operator +(int &i)
{return complex(real + i, imag);
}
complex complex::operator -(int &i)
{return complex(real - i, imag);
}
complex complex::operator *(int &i)
{return complex(real*i, imag*i);
}
complex complex::operator /(int &i)
{return complex(real / i, imag / i);
}
void complex::display()
{cout << "(" << real << "," << imag << "i)" << endl;
}int main()
{complex c1(1, 2), c2(3, 4), c3;int i = 5;cout << "c1=";c1.display();cout << "c2=";c2.display();c3 = c1 + c2;cout << "c1+c2=";c3.display();c3 = c1 - c2;cout << "c1-c2=";c3.display();c3 = c1*c2;cout << "c1*c2=";c3.display();c3 = c1 / c2;cout << "c1/c2=";c3.display();cout << "i=" << i << endl;c3 = c1 + i;cout << "c1+i=";c3.display();c3 = c1 - i;cout << "c1-i=";c3.display();c3 = c1*i;cout << "c1*i=";c3.display();c3 = c1 / i;cout << "c1/i=";c3.display();return 0;
}
2.使用友元函数完成运算符重载
#include <iostream>
using namespace std;
class Complex
{
public:Complex(){real = 0;imag = 0;}Complex(double r, double i){real = r;imag = i;}friend Complex operator+(Complex &c1, Complex &c2);friend Complex operator-(Complex &c1, Complex &c2);friend Complex operator*(Complex &c1, Complex &c2);friend Complex operator/(Complex &c1, Complex &c2);void display();
private:double real;double imag;
};//复数相加：(a+bi)+(c+di)=(a+c)+(b+d)i.
Complex operator+(Complex &c1, Complex &c2)
{Complex c;c.real = c1.real + c2.real;c.imag = c1.imag + c2.imag;return c;
}//复数相减：(a+bi)-(c+di)=(a-c)+(b-d)i.
Complex operator-(Complex &c1, Complex &c2)
{Complex c;c.real = c1.real - c2.real;c.imag = c1.imag - c2.imag;return c;
}//复数相乘：(a+bi)(c+di)=(ac－bd)+(bc+ad)i.
Complex operator*(Complex &c1, Complex &c2)
{Complex c;c.real = c1.real*c2.real - c1.imag*c2.imag;c.imag = c1.imag*c2.real + c1.real*c2.imag;return c;
}//复数相除：(a+bi)/(c+di)=(ac+bd)/(c^2+d^2) +(bc-ad)/(c^2+d^2)i
Complex operator/(Complex &c1, Complex &c2)
{Complex c;c.real = (c1.real*c2.real + c1.imag*c2.imag) / (c2.real*c2.real + c2.imag*c2.imag);c.imag = (c1.imag*c2.real - c1.real*c2.imag) / (c2.real*c2.real + c2.imag*c2.imag);return c;
}void Complex::display()
{cout << "(" << real << "," << imag << "i)" << endl;
}int main()
{Complex c1(3, 4), c2(5, -10), c3;cout << "c1=";c1.display();cout << "c2=";c2.display();c3 = c1 + c2;cout << "c1+c2=";c3.display();c3 = c1 - c2;cout << "c1-c2=";c3.display();c3 = c1*c2;cout << "c1*c2=";c3.display();c3 = c1 / c2;cout << "c1/c2=";c3.display();return 0;
}
类的友元函数可以通过类对象自由地访问该类对象的任何数据成员，这就是友元函数能够作为运算符函数的原因。
