C++

Reference

<functional>

class template
<functional>

std::logical_and

template <class T> struct logical_and;
Logical AND function object class
Binary function object class whose call returns the result of the logical "and" operation between its two arguments (as returned by operator &&).

Generically, function objects are instances of a class with member function operator() defined. This member function allows the object to be used with the same syntax as a function call.

It is defined with the same behavior as:

1
2
3
 
template <class T> struct logical_and : binary_function <T,T,bool> {
  bool operator() (const T& x, const T& y) const {return x&&y;}
};
 
1
2
3
4
5
6
 
template <class T> struct logical_and {
  bool operator() (const T& x, const T& y) const {return x&&y;}
  typedef T first_argument_type;
  typedef T second_argument_type;
  typedef bool result_type;
};

Template parameters

T
Type of the arguments passed to the functional call.
The type shall support the operation (operator&&).

Member types

member typedefinitionnotes
first_argument_typeTType of the first argument in member operator()
second_argument_typeTType of the second argument in member operator()
result_typeboolType returned by member operator()

Member functions

bool operator() (const T& x, const T& y)
Member function returning whether both its arguments are considered true (x&&y).

Example

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
 
// logical_and example
#include <iostream>     // std::cout, std::boolalpha
#include <functional>   // std::logical_and
#include <algorithm>    // std::transform

int main () {
  bool foo[] = {true,false,true,false};
  bool bar[] = {true,true,false,false};
  bool result[4];
  std::transform (foo, foo+4, bar, result, std::logical_and<bool>());
  std::cout << std::boolalpha << "Logical AND:\n";
  for (int i=0; i<4; i++)
    std::cout << foo[i] << " AND " << bar[i] << " = " << result[i] << "\n";
  return 0;
}

Output:

Logical AND:
true AND true = true
false AND true = false
true AND false = false
false AND false = false


See also

logical_or
Logical OR function object class (class template)
logical_not
Logical NOT function object class (class template)