Complex numbers

A complex number z = x + yi is the sum of a real number x and a real number y multiplied by the imaginary unit i, i ² = -1 ⇒ i = ±√(-1) , which is the solution of the equation x ² + 1 = 0.

Complex.h

namespace SmallWindows { 
  class NotaComplexNumber : public exception { 
    public: 
      NotaComplexNumber() {/* Empty. */} 
  }; 
 
  extern double Square(double value); 

The constructors, assignment operators, and the String conversion operator are similar to their counterparts in Rational:

  class Complex { 
    public: 
      Complex(double x = 0, double y = 0); 
      Complex(const Complex &complex); 
      Complex operator=(const Complex &complex); 
      bool ReadStream(const String& text); 
      Complex(const String& text); 
      operator String() const; 

When comparing two complex number, their absolute values (refer to Abs) are compared.

      bool operator==(const Complex &complex) const; 
      bool operator!=(const Complex...