This chapter is from the book
Types _Complex and _Imaginary
Before leaving this chapter it is worthy to note two other types in the language called _Complex and _Imaginary for working with complex and imaginary numbers.
Support for _Complex and _Imaginary types has been part of the ANSI C standard since C99, although C11 does make it optional. The best way to know if your compiler supports these types is to examine the summary of data types in Appendix A.