Contains private members (float type) realpart, imagepart; The constructor (for private member is initialized); Member function float Cangle (void) output plural real part, imaginary part and the vice of Angle
1. - by overloading the subtraction operator, direct implementation two complex direct subtraction calculation
2. The main function is defined in two classes of objects are respectively (2.2) and (1.1), and subtraction was calculated, and the output output the final result,