c8_complex_lib, a C++ code which defines complex numbers and the operations necessary to do arithmetic on them.

Since the ANSI C++ standard library now includes a complex class, the information described here is probably not of practical use. On the other hand, it may be helpful as a practical demonstration of how to define a useful arithmetic class.

The C8_COMPLEX class defines a c8_complex number as a pair of doubles. A variable c in this class may be declared by

        c8_complex c;
The declaration can include an initialization:

        c8_complex c = c8_complex ( 1.0, 2.0 );

A variable c declared as c8_complex may be assigned a value using the c8_complex() function:

        c = c8_complex ( a, b )
where a and b are double values; the assignment

        c = c8_complex ( a )
sets the real part of c to a, and the imaginary part to 0.

A variable c declared as c8_complex may be used in addition, subtraction, multiplication, or division with another c8_complex value, or a double value:

        c3 = c1 + c2;
        c3 = c1 - c2;
        c3 = c1 * c2;
        c3 = c1 / c2;

A variable c declared as c8_complex may be conjugated, or its real or imaginary part may be produced as a double value:

        c2 = ~c;
        d1 = c1.real ( );
        d2 = c1.imaginary ( );


The computer code and data files described and made available on this web page are distributed under the MIT license


c8_complex_lib is available in a C version and a C++ version.

Related Data and Programs:

C4_COMPLEX_LIB, a C++ code which defines a class called c4_complex for complex numbers with single precision components.


C8LIB, a C++ code which implements certain elementary functions for "C8" or double precision complex variables using the C++ "complex " datatype.

CPP, C++ codes which includes an example of the declaration and use of complex variables.


  1. Steve Oualline,
    Practical C++ Programming,
    O'Reilly & Associates, 1997,
    ISBN: 1-56592-139-9

Source Code:

Last revised on 12 February 2020.