A C++ Class for Complex Arithmetic

C4_COMPLEX_LIB is a C++ library 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 C4_COMPLEX class defines a c4_complex number as a pair of floats. A variable c in this class may be declared by

        c4_complex c;
The declaration can include an initialization:

        c4_complex c = c4_complex ( 1.0, 2.0 );

A variable c declared as c4_complex may be assigned a value using the c4_complex() function:

        c = c4_complex ( a, b )
where a and b are float values; the assignment

        c = c4_complex ( a )
sets the real part of c to a, and the imaginary part to 0.

A variable c declared as c4_complex may be used in addition, subtraction, multiplication, or division with another c4_complex value, or a float value:

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

A variable c declared as c4_complex may be conjugated, or its real or imaginary part may be produced as a float 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 GNU LGPL license.


C4_COMPLEX_LIB is available in a C version and a C++ version.

Related Data and Programs:

C4LIB, a C++ library which implements certain elementary functions for "C4" or single precision complex variables using the C++ "complex " datatype.

C8_COMPLEX_LIB, a C++ library which defines a class called c8_complex for complex numbers with double precision components.

CPP, C++ programs 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:

Examples and Tests:

You can go up one level to the C++ source codes.

Last revised on 27 September 2013.