Returns an iterator to the first element in a set with a key that is equal to or greater than a specified key.
const_iterator lower_bound(
const Key& _Key
) const;
iterator lower_bound(
const Key& _Key
);
Parameters
- _Key
The argument key to be compared with the sort key of an element from the set being searched.
Return Value
An iterator or const_iterator that addresses the ___location of an element in a set that with a key that is equal to or greater than the argument key or that addresses the ___location succeeding the last element in the set if no match is found for the key.
Example
// set_lower_bound.cpp
// compile with: /EHsc
#include <set>
#include <iostream>
int main( )
{
using namespace std;
set <int> s1;
set <int> :: const_iterator s1_AcIter, s1_RcIter;
s1.insert( 10 );
s1.insert( 20 );
s1.insert( 30 );
s1_RcIter = s1.lower_bound( 20 );
cout << "The element of set s1 with a key of 20 is: "
<< *s1_RcIter << "." << endl;
s1_RcIter = s1.lower_bound( 40 );
// If no match is found for the key, end( ) is returned
if ( s1_RcIter == s1.end( ) )
cout << "The set s1 doesn't have an element "
<< "with a key of 40." << endl;
else
cout << "The element of set s1 with a key of 40 is: "
<< *s1_RcIter << "." << endl;
// The element at a specific ___location in the set can be found
// by using a dereferenced iterator that addresses the ___location
s1_AcIter = s1.end( );
s1_AcIter--;
s1_RcIter = s1.lower_bound( *s1_AcIter );
cout << "The element of s1 with a key matching "
<< "that of the last element is: "
<< *s1_RcIter << "." << endl;
}
The element of set s1 with a key of 20 is: 20. The set s1 doesn't have an element with a key of 40. The element of s1 with a key matching that of the last element is: 30.
Requirements
Header: <set>
Namespace: std
See Also
Reference
set::lower_bound, set::upper_bound, and set::equal_range