<queue> operators
The latest version of this topic can be found at <queue> operators.
| operator!= | operator> | operator>= |
| operator< | operator<= | operator== |
operator!=
Tests if the queue object on the left side of the operator is not equal to the queue object on the right side.
bool operator!=(const queue <Type, Container>& left, const queue <Type, Container>& right,);
Parameters
left
An object of type queue.
right
An object of type queue.
Return Value
true if the queues are not equal; false if queues are equal.
Remarks
The comparison between queue objects is based on a pairwise comparison of their elements. Two queues are equal if they have the same number of elements and their respective elements have the same values. Otherwise, they are unequal.
Example
// queue_op_ne.cpp
// compile with: /EHsc
#include <queue>
#include <list>
#include <iostream>
int main( )
{
using namespace std;
// Declares queues with list base containers
queue <int, list<int> > q1, q2, q3;
// The following line would have caused an error because vector
// does not support pop_front( ) and so cannot be adapted
// by queue as a base container
// queue <int, vector<int> > q1, q2, q3;
q1.push( 1 );
q2.push( 1 );
q2.push( 2 );
q3.push( 1 );
if ( q1 != q2 )
cout << "The queues q1 and q2 are not equal." << endl;
else
cout << "The queues q1 and q2 are equal." << endl;
if ( q1 != q3 )
cout << "The queues q1 and q3 are not equal." << endl;
else
cout << "The queues q1 and q3 are equal." << endl;
}
The queues q1 and q2 are not equal.
The queues q1 and q3 are equal.
operator<
Tests if the queue object on the left side of the operator is less than the queue object on the right side.
bool operator<(const queue <Type, Container>& left, const queue <Type, Container>& right,);
Parameters
left
An object of type queue.
right
An object of type queue.
Return Value
true if the queue on the left side of the operator is less than and not equal to the queue on the right side of the operator; otherwise false.
Remarks
The comparison between queue objects is based on a pairwise comparison of their elements. The less-than relationship between two queue objects is based on a comparison of the first pair of unequal elements.
Example
// queue_op_lt.cpp
// compile with: /EHsc
#include <queue>
#include <iostream>
int main( )
{
using namespace std;
// Declares queues with default deque base container
queue <int> q1, q2, q3;
q1.push( 1 );
q1.push( 2 );
q2.push( 5 );
q2.push( 10 );
q3.push( 1 );
q3.push( 2 );
if ( q1 < q2 )
cout << "The queue q1 is less than the queue q2." << endl;
else
cout << "The queue q1 is not less than the queue q2." << endl;
if ( q1 < q3 )
cout << "The queue q1 is less than the queue q3." << endl;
else
cout << "The queue q1 is not less than the queue q3." << endl;
}
The queue q1 is less than the queue q2.
The queue q1 is not less than the queue q3.
operator<=
Tests if the queue object on the left side of the operator is less than or equal to the queue object on the right side.
bool operator<=(const queue <Type, Container>& left, const queue <Type, Container>& right,);
Parameters
left
An object of type queue.
right
An object of type queue.
Return Value
true if the queue on the left side of the operator is strictly less than the queue on the right side of the operator; otherwise false.
Remarks
The comparison between queue objects is based on a pairwise comparison of their elements. The less than or equal to relationship between two queue objects is based on a comparison of the first pair of unequal elements.
Example
// queue_op_le.cpp
// compile with: /EHsc
#include <queue>
#include <iostream>
int main( )
{
using namespace std;
queue <int> q1, q2, q3;
q1.push( 5 );
q1.push( 10 );
q2.push( 1 );
q2.push( 2 );
q3.push( 5 );
q3.push( 10 );
if ( q1 <= q2 )
cout << "The queue q1 is less than or equal to "
<< "the queue q2." << endl;
else
cout << "The queue q1 is greater than "
<< "the queue q2." << endl;
if ( q1 <= q3 )
cout << "The queue q1 is less than or equal to "
<< "the queue q3." << endl;
else
cout << "The queue q1 is greater than "
<< "the queue q3." << endl;
}
The queue q1 is greater than the queue q2.
The queue q1 is less than or equal to the queue q3.
operator==
Tests if the queue object on the left side of the operator is equal to queue object on the right side.
bool operator==(const queue <Type, Container>& left, const queue <Type, Container>& right,);
Parameters
left
An object of type queue.
right
An object of type queue.
Return Value
true if the queues are not equal; false if queues are equal.
Remarks
The comparison between queue objects is based on a pairwise comparison of their elements. Two queues are equal if they have the same number of elements and their respective elements have the same values. Otherwise, they are unequal.
Example
// queue_op_eq.cpp
// compile with: /EHsc
#include <queue>
#include <list>
#include <iostream>
int main( )
{
using namespace std;
// Declares queues with list base containers
queue <int, list<int> > q1, q2, q3;
// The following line would have caused an error because vector
// does not support pop_front( ) and so cannot be adapted
// by queue as a base container
// queue <int, vector<int> > q1, q2, q3;
q1.push( 1 );
q2.push( 2 );
q3.push( 1 );
if ( q1 != q2 )
cout << "The queues q1 and q2 are not equal." << endl;
else
cout << "The queues q1 and q2 are equal." << endl;
if ( q1 != q3 )
cout << "The queues q1 and q3 are not equal." << endl;
else
cout << "The queues q1 and q3 are equal." << endl;
}
The queues q1 and q2 are not equal.
The queues q1 and q3 are equal.
operator>
Tests if the queue object on the left side of the operator is greater than the queue object on the right side.
bool operator>(const queue <Type, Container>& left, const queue <Type, Container>& right,);
Parameters
left
An object of type queue.
right
An object of type queue.
Return Value
true if the queue on the left side of the operator is strictly less than the queue on the right side of the operator; otherwise false.
Remarks
The comparison between queue objects is based on a pairwise comparison of their elements. The greater-than relationship between two queue objects is based on a comparison of the first pair of unequal elements.
Example
// queue_op_gt.cpp
// compile with: /EHsc
#include <queue>
#include <iostream>
int main( )
{
using namespace std;
queue <int> q1, q2, q3;
q1.push( 1 );
q1.push( 2 );
q1.push( 3 );
q2.push( 5 );
q2.push( 10 );
q3.push( 1 );
q3.push( 2 );
if ( q1 > q2 )
cout << "The queue q1 is greater than "
<< "the queue q2." << endl;
else
cout << "The queue q1 is not greater than "
<< "the queue q2." << endl;
if ( q1> q3 )
cout << "The queue q1 is greater than "
<< "the queue q3." << endl;
else
cout << "The queue q1 is not greater than "
<< "the queue q3." << endl;
}
The queue q1 is not greater than the queue q2.
The queue q1 is greater than the queue q3.
operator>=
Tests if the queue object on the left side of the operator is greater than or equal to the queue object on the right side.
bool operator>=(const queue <Type, Container>& left, const queue <Type, Container>& right,);
Parameters
left
An object of type queue.
right
An object of type queue.
Return Value
true if the queue on the left side of the operator is strictly less than the queue on the right side of the operator; otherwise false.
Remarks
The comparison between queue objects is based on a pairwise comparison of their elements. Two queues are equal if they have the same number of elements and their respective elements have the same values. Otherwise, they are unequal.
Example
// queue_op_ge.cpp
// compile with: /EHsc
#include <queue>
#include <iostream>
int main( )
{
using namespace std;
queue <int> q1, q2, q3;
q1.push( 1 );
q1.push( 2 );
q2.push( 5 );
q2.push( 10 );
q3.push( 1 );
q3.push( 2 );
if ( q1 >= q2 )
cout << "The queue q1 is greater than or equal to "
<< "the queue q2." << endl;
else
cout << "The queue q1 is less than "
<< "the queue q2." << endl;
if ( q1>= q3 )
cout << "The queue q1 is greater than or equal to "
<< "the queue q3." << endl;
else
cout << "The queue q1 is less than "
<< "the queue q3." << endl;
}
The queue q1 is less than the queue q2.
The queue q1 is greater than or equal to the queue q3.