Define a complex type, real component with real variables, imaginary part with image variables, and are based on double, and write the main function test,

Requirements:

(1) when creating objects don't pass parameters, the real, the image is 0; When introduced into a real component parameters, the real=incoming parameters, image=0;

2 defines a "*" (multiply) operator overloading, overloaded member function, realization of plural multiplication,