\begin{ccRefFunction}{is_one} \ccDefinition The function \ccRefName\ determines if a value is equal to 1 or not.\\ The function is guaranteed to be well defined in case the argument type is a model of the \ccc{IntegralDomainWithoutDivision} concept. \ccInclude{CGAL/number_utils.h} \ccFunction{template result_type is_one(const NT& x);} { The \ccc{result_type} is convertible to \ccc{bool}. } \ccSeeAlso \ccRefConceptPage{IntegralDomainWithoutDivision}\\ \ccRefConceptPage{AlgebraicStructureTraits::IsOne}\\ \end{ccRefFunction}