rename the code files

lectures/14_operators/complex.h

@@ -0,0 +1,29 @@
+#include <iostream>
+using std::istream;
+using std::ostream;
+
+class Complex {
+public:
+  Complex(double x=0, double y=0) : real_(x), imag_(y) {}  // default constructor
+  Complex(Complex const& old) : real_(old.real_), imag_(old.imag_) {}  // copy constructor
+  Complex& operator= (Complex const& rhs); // Assignment operator
+  double Real() const { return real_; }
+  void SetReal(double x) { real_ = x; }
+  double Imaginary() const { return imag_; }
+  void SetImaginary(double y) { imag_ = y; }
+  double Magnitude() const { return sqrt(real_*real_ + imag_*imag_); }
+  Complex operator+ (Complex const& rhs) const;  
+  Complex operator- () const; // unary operator- negates a complex number
+
+  // Input and output stream operators can not be member functions.  They can be friends, 
+  // or they can be non-member functions if their work can be accomplished through the 
+  // public interface to the class.  Note that the complex object passed to the istream 
+  // (>>) operator MUST be passed as a non-const reference.
+  friend istream& operator>> (istream& istr, Complex& c);
+private:
+  double real_, imag_;
+};
+
+Complex operator- (Complex const& left, Complex const& right); // non-member function
+ostream& operator<< (ostream& ostr, Complex const& c);  // non-member function
+