.\" ident @(#)less.3 .\" Standard Template Library .\" $$RW_INSERT_HEADER "slyrs.man" .TH less 3C++ "02 Apr 1998" "Rogue Wave Software" "-" .ce2 Standard C++ Library Copyright 1998, Rogue Wave Software, Inc. .SH NAME \f2less\fP \ - A binary function object that returns \f2true\fP if its first argument is less than its second. .SH SYNOPSIS .br #include .br template .br struct less : public binary_function; .SH DESCRIPTION less is a binary function object. Its \f2operator()\fP returns \f2true\fP if \f2x\fP is less than \f2y\fP. You can pass a less object to any algorithm that requires a binary function. For example, the transform algorithm applies a binary operation to corresponding values in two collections and stores the result of the function. less would be used in that algorithm in the following manner: .br vector vec1; .br vector vec2; .br vector vecResult; .br . .br . .br . .br transform(vec1.begin(), vec1.end(), .RE .RS 9 vec2.begin(), .br vecResult.begin(), less()); .RE After this call to transform, \f2vecResult(n)\fP contains a \f21\fP if \f2vec1(n)\fP was less than \f2vec2(n)\fP or a \f20\fP if \f2vec1(n)\fP was greater than or equal to \f2vec2(n)\fP. .SH INTERFACE .RE .RS 0 template .br struct less : binary_function { .RE .RS 1 bool operator() (const T&, const T&) const; .RE .RS 0 }; .SH WARNINGS If your compiler does not support default template parameters, then you always need to supply the \f2Allocator\fP template argument. For instance, you have to write: \f2vector >\fP instead of \f2vector\fP If your compiler does not support namespaces, then you do not need the using declaration for \f2std\fP. .SH SEE ALSO binary_function, Function_Objects