# Function COMPLEX

### Syntax

• complex realpart `&optional` imagpartcomplex ====Arguments and Values==== * realpart - a real. * imagpart - a real. * complex - a rational or a complex. ====Description==== complex returns a number whose real part is realpart and whose imaginary part is imagpart. If realpart is a rational and imagpart is the rational number zero, the result of complex is realpart, a rational. Otherwise, the result is a complex. If either realpart or imagpart is a float, the non-float is converted to a float before the complex is created. If imagpart is not supplied, the imaginary part is a zero of the same type as realpart; i.e. `(coerce 0 (type-of realpart))` is effectively used. Type upgrading implies a movement upwards in the type hierarchy lattice. In the case of complexes, the type-specifier must be a subtype of `(upgraded-complex-part-type type-specifier)`. If type-specifier1 is a subtype of type-specifier2, then `(upgraded-complex-element-type 'type-specifier1)` must also be a subtype of `(upgraded-complex-element-type 'type-specifier2)`. Two disjoint types can be upgraded into the same thing. `#| TODO: fix this sentence, it doesn't make sense here. |#` ====Examples==== <blockquote> (complex 0) <r>0 </r> (complex 0.0) <r>#C(0.0 0.0) </r> (complex 1 1/2) <r>#C(1 1/2)</r> (complex 1 .99) <r>#C(1.0 0.99) </r> (complex 3/2 0.0) <r>#C(1.5 0.0) </r> </blockquote> ====Side Effects==== None. ====Affected By==== None. ====Exceptional Situations==== None. ====See Also==== * Function REALPART * Function IMAGPART**
• {\secref\SharpsignC}

None.