<list> operators
The latest version of this topic can be found at <list> operators.
| operator!= | operator> | operator>= |
| operator< | operator<= | operator== |
operator!=
Tests if the list object on the left side of the operator is not equal to the list object on the right side.
bool operator!=(
const list<Type, Allocator>&
left,
const list<Type, Allocator>& right);
Parameters
left
An object of type list.
right
An object of type list.
Return Value
true if the lists are not equal; false if the lists are equal.
Remarks
The comparison between list objects is based on a pairwise comparison of their elements. Two lists are equal if they have the same number of elements and their respective elements have the same values. Otherwise, they are unequal.
Example
// list_op_ne.cpp
// compile with: /EHsc
#include <list>
#include <iostream>
int main( )
{
using namespace std;
list <int> c1, c2;
c1.push_back( 1 );
c2.push_back( 2 );
if ( c1 != c2 )
cout << "Lists not equal." << endl;
else
cout << "Lists equal." << endl;
}
\* Output:
Lists not equal.
*\
operator<
Tests if the list object on the left side of the operator is less than the list object on the right side.
bool operator<(
const list<Type, Allocator>&
left,
const list<Type, Allocator>& right);
Parameters
left
An object of type list.
right
An object of type list.
Return Value
true if the list on the left side of the operator is less than but not equal to the list on the right side of the operator; otherwise false.
Remarks
The comparison between list objects is based on a pairwise comparison of their elements. The less-than relationship between two objects is based on a comparison of the first pair of unequal elements.
Example
// list_op_lt.cpp
// compile with: /EHsc
#include <list>
#include <iostream>
int main( )
{
using namespace std;
list <int> c1, c2;
c1.push_back( 1 );
c1.push_back( 2 );
c1.push_back( 4 );
c2.push_back( 1 );
c2.push_back( 3 );
if ( c1 < c2 )
cout << "List c1 is less than list c2." << endl;
else
cout << "List c1 is not less than list c2." << endl;
}
\* Output:
List c1 is less than list c2.
*\
operator<=
Tests if the list object on the left side of the operator is less than or equal to the list object on the right side.
bool operator<=(
const list<Type, Allocator>&
left,
const list<Type, Allocator>& right);
Parameters
left
An object of type list.
right
An object of type list.
Return Value
true if the list on the left side of the operator is less than or equal to the list on the right side of the operator; otherwise false.
Remarks
The comparison between list objects is based on a pairwise comparison of their elements. The less than or equal to relationship between two objects is based on a comparison of the first pair of unequal elements.
Example
// list_op_le.cpp
// compile with: /EHsc
#include <list>
#include <iostream>
int main( )
{
using namespace std;
list <int> c1, c2;
c1.push_back( 1 );
c1.push_back( 2 );
c1.push_back( 4 );
c2.push_back( 1 );
c2.push_back( 3 );
if ( c1 <= c2 )
cout << "List c1 is less than or equal to list c2." << endl;
else
cout << "List c1 is greater than list c2." << endl;
}
\* Output:
List c1 is less than or equal to list c2.
*\
operator==
Tests if the list object on the left side of the operator is equal to the list object on the right side.
bool operator==(
const list<Type, Allocator>&
left,
const list<Type, Allocator>& right);
Parameters
left
An object of type list.
right
An object of type list.
Return Value
true if the list on the left side of the operator is equal to the list on the right side of the operator; otherwise false.
Remarks
The comparison between list objects is based on a pairwise comparison of their elements. Two lists are equal if they have the same number of elements and their respective elements have the same values. Otherwise, they are unequal.
Example
// list_op_eq.cpp
// compile with: /EHsc
#include <list>
#include <iostream>
int main( )
{
using namespace std;
list <int> c1, c2;
c1.push_back( 1 );
c2.push_back( 1 );
if ( c1 == c2 )
cout << "The lists are equal." << endl;
else
cout << "The lists are not equal." << endl;
}
\* Output:
The lists are equal.
*\
operator>
Tests if the list object on the left side of the operator is greater than the list object on the right side.
bool operator>(
const list<Type, Allocator>&
left,
const list<Type, Allocator>& right);
Parameters
left
An object of type list.
right
An object of type list.
Return Value
true if the list on the left side of the operator is greater than the list on the right side of the operator; otherwise false.
Remarks
The comparison between list objects is based on a pairwise comparison of their elements. The greater-than relationship between two objects is based on a comparison of the first pair of unequal elements.
Example
// list_op_gt.cpp
// compile with: /EHsc
#include <list>
#include <iostream>
int main( )
{
using namespace std;
list <int> c1, c2;
c1.push_back( 1 );
c1.push_back( 3 );
c1.push_back( 1 );
c2.push_back( 1 );
c2.push_back( 2 );
c2.push_back( 2 );
if ( c1 > c2 )
cout << "List c1 is greater than list c2." << endl;
else
cout << "List c1 is not greater than list c2." << endl;
}
\* Output:
List c1 is greater than list c2.
*\
operator>=
Tests if the list object on the left side of the operator is greater than or equal to the list object on the right side.
bool operator>=(
const list<Type, Allocator>&
left,
const list<Type, Allocator>& right);
Parameters
left
An object of type list.
right
An object of type list.
Return Value
true if the list on the left side of the operator is greater than or equal to the list on the right side of the operator; otherwise false.
Remarks
The comparison between list objects is based on a pairwise comparison of their elements. The greater than or equal to relationship between two objects is based on a comparison of the first pair of unequal elements.
Example
// list_op_ge.cpp
// compile with: /EHsc
#include <list>
#include <iostream>
int main( )
{
using namespace std;
list <int> c1, c2;
c1.push_back( 1 );
c1.push_back( 3 );
c1.push_back( 1 );
c2.push_back( 1 );
c2.push_back( 2 );
c2.push_back( 2 );
if ( c1 >= c2 )
cout << "List c1 is greater than or equal to list c2." << endl;
else
cout << "List c1 is less than list c2." << endl;
}
\* Output:
List c1 is greater than or equal to list c2.
*\