Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

PrevUpHomeNext
less than

Lexicographically compare two sequences.

Synopsis
template <typename Seq1, typename Seq2>
bool
operator<(Seq1 const& a, Seq2 const& b);
Parameters

Parameter

Requirement

Description

a, b

Instances of Sequence

Sequence(s) to compare

Expression Semantics
a < b

Return type: bool

Requirements:

For each element, e1, in sequence a, and for each element, e2, in sequence b, a < b is a valid expression returning a type that is convertible to bool.

An attempt to compare two Sequences of different lengths results in a compile time error.

Semantics: Returns the lexicographical comparison of between a and b.

Header
#include <boost/fusion/sequence/comparison/less.hpp>
#include <boost/fusion/include/less.hpp>
Example
vector<int, float> v1(4, 3.3f);
vector<short, float> v2(5, 3.3f);
vector<long, double> v3(5, 4.4);
assert(v1 < v2);
assert(v2 < v3);

PrevUpHomeNext