less_equal Struct
A binary predicate that tests whether a value of a specified type is less than or equal to another value of that type.
template<class Type>
struct less_equal : public binary_function <Type, Type, bool>
{
bool operator()(
const Type& _Left,
const Type& _Right
) const;
};
Parameters
_Left
The left operand of type Type in the inequality to be tested._Right
The right operand of type Type in the inequality to be tested.
Return Value
true if _Left <= _Right; false if _Left > _Right.
Remarks
The binary predicate less_equal<Type> provides a strict weak ordering of a set of element values of type Type into equivalence classes if and only if this Type satisfies the standard mathematical requirements for being so ordered. The specializations for any pointer type yield a total ordering of elements in that all elements of distinct values are ordered with respect to each other.
Example
// functional_less_equal.cpp
// compile with: /EHsc
#define _CRT_RAND_S
#include <stdlib.h>
#include <vector>
#include <algorithm>
#include <functional>
#include <cstdlib>
#include <iostream>
int main( )
{
using namespace std;
vector <int> v1;
vector <int>::iterator Iter1;
vector <int>::reverse_iterator rIter1;
unsigned int randomNumber;
int i;
for ( i = 0 ; i < 5 ; i++ )
{
if ( rand_s( &randomNumber ) == 0 )
{
// Convert the random number to be between 1 - 50000
// This is done for readability purposes
randomNumber = ( unsigned int) ((double)randomNumber /
(double) UINT_MAX * 50000) + 1;
v1.push_back( randomNumber );
}
}
for ( i = 0 ; i < 3 ; i++ )
{
v1.push_back( 2836 );
}
cout << "Original vector v1 = ( " ;
for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
cout << *Iter1 << " ";
cout << ")" << endl;
// To sort in ascending order,
// use the binary predicate less_equal<int>( )
sort( v1.begin( ), v1.end( ), less_equal<int>( ) );
cout << "Sorted vector v1 = ( " ;
for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
cout << *Iter1 << " ";
cout << ")" << endl;
}
Sample Output
Original vector v1 = ( 31247 37154 48755 15251 6205 2836 2836 2836 )
Sorted vector v1 = ( 2836 2836 2836 6205 15251 31247 37154 48755 )
Requirements
Header: <functional>
Namespace: std