logical_or Struct

The struct provides a predefined function object that performs the logical operation of disjunction on elements of a specified value type and tests for the truth or falsity of the result.

template<class Type>
   struct logical_or : 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 disjunction to be tested.

• _Right
  The right operand of type Type in the disjunction to be tested.

Return Value

true if _Left is true or _Right is true; false if and only if _Left is false and _Right is false.

Example

// functional_logical_or.cpp
// compile with: /EHsc
#include <deque>
#include <algorithm>
#include <functional>
#include <iostream>

int main( )
{
   using namespace std;
   deque <bool> d1, d2, d3( 7 );
   deque <bool>::iterator iter1, iter2, iter3;

   int i;
   for ( i = 0 ; i < 7 ; i++ )
   {
      d1.push_back((bool)((rand() % 2) != 0));
   }

   int j;
   for ( j = 0 ; j < 7 ; j++ )
   {
      d2.push_back((bool)((rand() % 2) != 0));
   }

   cout << boolalpha;    // boolalpha I/O flag on

   cout << "Original deque:\n d1 = ( " ;
   for ( iter1 = d1.begin( ) ; iter1 != d1.end( ) ; iter1++ )
      cout << *iter1 << " ";
   cout << ")" << endl;

   cout << "Original deque:\n d2 = ( " ;
   for ( iter2 = d2.begin( ) ; iter2 != d2.end( ) ; iter2++ )
      cout << *iter2 << " ";
   cout << ")" << endl;

   // To find element-wise disjunction of the truth values
   // of d1 & d2, use the logical_or function object
   transform( d1.begin( ), d1.end( ), d2.begin( ),
      d3.begin( ), logical_or<bool>( ) );
   cout << "The deque which is the disjuction of d1 & d2 is:\n d3 = ( " ;
   for ( iter3 = d3.begin( ) ; iter3 != d3.end( ) ; iter3++ )
      cout << *iter3 << " ";
   cout << ")" << endl;
}

Original deque:
 d1 = ( true true false false true false false )
Original deque:
 d2 = ( false false false true true true true )
The deque which is the disjuction of d1 & d2 is:
 d3 = ( true true false true true true true )

Requirements

Header: <functional>

Namespace: std

See Also

Concepts

<functional> Members

Thread Safety in the Standard C++ Library

Standard Template Library