boost::algorithm::none_of() in C++ library
Last Updated :
30 May, 2019
The none_of() function in C++ boost library is found under the header ‘boost/algorithm/cxx11/none_of.hpp’ which tests all the elements of a sequence and returns true if all of them do not share a property. It takes a sequence and a predicate, and returns true if the predicate returns false when applied to every element in the sequence.
Syntax:
bool none_of ( InputIterator first, InputIterator last, Predicate p )
or
bool none_of ( const Range &R, Predicate p)
Parameters: The function accepts parameters as described below:
- first: It specifies the input iterators to the initial positions in a sequence.
- second: It specifies the input iterators to the final positions in a sequence.
- p: It specifies a unary predicate function that accepts an element and returns a bool.
- R: It is the complete sequence.
Return Value: The function returns true if the given predicate is false for all the elements of the sequence, else it returns false.
Below is the implementation of the above approach:
Program-1:
#include <bits/stdc++.h>
#include <boost/algorithm/cxx11/none_of.hpp>
using namespace std;
bool isOdd( int i)
{
return i % 2 == 1;
}
int main()
{
vector< int > c(5, 1);
bool ans
= boost::algorithm::none_of(c, isOdd);
if (ans == 1)
cout << "all are not odd" ;
else
cout << "all are odd" ;
return 0;
}
|
Program-2:
#include <bits/stdc++.h>
#include <boost/algorithm/cxx11/none_of.hpp>
using namespace std;
bool noneLessThanSeven( int i)
{
return i < 7;
}
int main()
{
int a[] = { 1, 2, 5, 6 };
bool ans
= boost::algorithm::none_of(a, a + 4,
noneLessThanSeven);
if (ans == 1)
cout << "all greater than 7" ;
else
cout << "all smaller than 7" ;
return 0;
}
|
Output:
all smaller than 7
Reference: https://www.boost.org/doc/libs/1_70_0/libs/algorithm/doc/html/the_boost_algorithm_library/CXX11/none_of.html
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