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<stack> operators

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operator!=

Tests if the stack object on the left side of the operator is not equal to stack object on the right side.

bool operator!=(const stack <Type, Container>& left, const stack <Type, Container>& right,);

Parameters

left
An object of type stack.

right
An object of type stack.

Return Value

true if the stacks or stacks are not equal; false if stacks or stacks are equal.

Remarks

The comparison between stacks objects is based on a pairwise comparison of their elements. Two stacks are equal if they have the same number of elements and their respective elements have the same values. Otherwise, they are unequal.

Example

// stack_op_me.cpp
// compile with: /EHsc
#include <stack>
#include <vector>
#include <iostream>

int main( )
{
   using namespace std;

   // Declares stacks with vector base containers
   stack <int, vector<int> > s1, s2, s3;

   // The following would have cause an error because stacks with
   // different base containers are not equality comparable
   // stack <int, list<int> >  s3;

   s1.push( 1 );
   s2.push( 2 );
   s3.push( 1 );

   if ( s1 != s2 )
      cout << "The stacks s1 and s2 are not equal." << endl;
   else
      cout << "The stacks s1 and s2 are equal." << endl;

   if ( s1 != s3 )
      cout << "The stacks s1 and s3 are not equal." << endl;
   else
      cout << "The stacks s1 and s3 are equal." << endl;
}

The stacks s1 and s2 are not equal.
The stacks s1 and s3 are equal.

operator<

Tests if the stack object on the left side of the operator is less than the stack object on the right side.

bool operator<(const stack <Type, Container>& left, const stack <Type, Container>& right);

Parameters

left
An object of type stack.

right
An object of type stack.

Return Value

true if the stack on the left side of the operator is less than and not equal to the stack on the right side of the operator; otherwise false.

Remarks

The comparison between stack objects is based on a pairwise comparison of their elements. The less-than relationship between two stack objects is based on a comparison of the first pair of unequal elements.

Example

// stack_op_lt.cpp
// compile with: /EHsc
#include <stack>
#include <list>
#include <iostream>

int main( )
{
   using namespace std;

   // Declares stacks with list base container
   stack <int, list<int> > s1, s2, s3;

   s1.push( 2 );
   s1.push( 4 );
   s1.push( 6 );
   s1.push( 8 );
   s2.push( 5 );
   s2.push( 10 );
   s3.push( 2 );
   s3.push( 4 );
   s3.push( 6 );
   s3.push( 8 );

   if ( s1 >= s2 )
      cout << "The stack s1 is greater than or equal to "
           << "the stack s2." << endl;
   else
      cout << "The stack s1 is less than "
           << "the stack s2." << endl;

   if ( s1>= s3 )
      cout << "The stack s1 is greater than or equal to "
           << "the stack s3." << endl;
   else
      cout << "The stack s1 is less than "
           << "the stack s3." << endl;

   // to print out the stack s1 ( by unstacking the elements):
   stack <int>::size_type i_size_s1 = s1.size( );
   cout << "The stack s1 from the top down is: ( ";
   unsigned int i;
   for ( i = 1 ; i <= i_size_s1 ; i++ )
   {
      cout << s1.top( ) << " ";
      s1.pop( );
   }
   cout << ")." << endl;
}

The stack s1 is less than the stack s2.
The stack s1 is greater than or equal to the stack s3.
The stack s1 from the top down is: ( 8 6 4 2 ).

operator<=

Tests if the stack object on the left side of the operator is less than or equal to the stack object on the right side.

bool operator<=(const stack <Type, Container>& left, const stack <Type, Container>& right);

Parameters

left
An object of type stack.

right
An object of type stack.

Return Value

true if the stack on the left side of the operator is less than or equal to the stack on the right side of the operator; otherwise false.

Remarks

The comparison between stack objects is based on a pairwise comparison of their elements. The less than or equal to relationship between two stack objects is based on a comparison of the first pair of unequal elements.

Example

// stack_op_le.cpp
// compile with: /EHsc
#include <stack>
#include <iostream>

int main( )
{
   using namespace std;

   // Declares stacks with default deque base container
   stack <int> s1, s2, s3;

   s1.push( 5 );
   s1.push( 10 );
   s2.push( 1 );
   s2.push( 2 );
   s3.push( 5 );
   s3.push( 10 );

   if ( s1 <= s2 )
      cout << "The stack s1 is less than or equal to "
           << "the stack s2." << endl;
   else
      cout << "The stack s1 is greater than "
           << "the stack s2." << endl;

   if ( s1 <= s3 )
      cout << "The stack s1 is less than or equal to "
           << "the stack s3." << endl;
   else
      cout << "The stack s1 is greater than "
           << "the stack s3." << endl;
}

The stack s1 is greater than the stack s2.
The stack s1 is less than or equal to the stack s3.

operator==

Tests if the stack object on the left side of the operator is equal to stack object on the right side.

bool operator==(const stack <Type, Container>& left, const stack <Type, Container>& right);

Parameters

left
An object of type stack.

right
An object of type stack.

Return Value

true if the stacks or stacks are equal; false if stacks or stacks are not equal.

Remarks

The comparison between stack objects is based on a pairwise comparison of their elements. Two stacks are equal if they have the same number of elements and their respective elements have the same values. Otherwise, they are unequal.

Example

// stack_op_eq.cpp
// compile with: /EHsc
#include <stack>
#include <vector>
#include <iostream>

int main( )
{
   using namespace std;

   // Declares stacks with vector base containers
   stack <int, vector<int> > s1, s2, s3;

   // The following would have cause an error because stacks with
   // different base containers are not equality comparable
   // stack <int, list<int> > s3;

   s1.push( 1 );
   s2.push( 2 );
   s3.push( 1 );

   if ( s1 == s2 )
      cout << "The stacks s1 and s2 are equal." << endl;
   else
      cout << "The stacks s1 and s2 are not equal." << endl;

   if ( s1 == s3 )
      cout << "The stacks s1 and s3 are equal." << endl;
   else
      cout << "The stacks s1 and s3 are not equal." << endl;
}

The stacks s1 and s2 are not equal.
The stacks s1 and s3 are equal.

operator>

Tests if the stack object on the left side of the operator is greater than the stack object on the right side.

bool operator>(const stack <Type, Container>& left, const stack <Type, Container>& right);

Parameters

left
An object of type stack.

right
An object of type stack.

Return Value

true if the stack on the left side of the operator is greater than and not equal to the stack on the right side of the operator; otherwise false.

Remarks

The comparison between stack objects is based on a pairwise comparison of their elements. The greater-than relationship between two stack objects is based on a comparison of the first pair of unequal elements.

Example

// stack_op_gt.cpp
// compile with: /EHsc
#include <stack>
#include <list>
#include <iostream>

int main( )
{
   using namespace std;

   // Declares stacks with list base container
   stack <int, list<int> > s1, s2, s3;

   s1.push( 1 );
   s1.push( 2 );
   s1.push( 3 );
   s2.push( 5 );
   s2.push( 10 );
   s3.push( 1 );
   s3.push( 2 );

   if ( s1 > s2 )
      cout << "The stack s1 is greater than "
           << "the stack s2." << endl;
   else
      cout << "The stack s1 is not greater than "
           << "the stack s2." << endl;

   if ( s1> s3 )
      cout << "The stack s1 is greater than "
           << "the stack s3." << endl;
   else
      cout << "The stack s1 is not greater than "
           << "the stack s3." << endl;
}

The stack s1 is not greater than the stack s2.
The stack s1 is greater than the stack s3.

operator>=

Tests if the stack object on the left side of the operator is greater than or equal to the stack object on the right side.

bool operator>=(const stack <Type, Container>& left, const stack <Type, Container>& right);

Parameters

left
An object of type stack.

right
An object of type stack.

Return Value

true if the stack on the left side of the operator is strictly less than the stack on the right side of the operator; otherwise false.

Remarks

The comparison between stack objects is based on a pairwise comparison of their elements. The greater than or equal to relationship between two stack objects is based on a comparison of the first pair of unequal elements.

Example

// stack_op_ge.cpp
// compile with: /EHsc
#include <stack>
#include <list>
#include <iostream>

int main( )
{
   using namespace std;

   // Declares stacks with list base container
   stack <int, list<int> > s1, s2, s3;

   s1.push( 1 );
   s1.push( 2 );
   s2.push( 5 );
   s2.push( 10 );
   s3.push( 1 );
   s3.push( 2 );

   if ( s1 >= s2 )
      cout << "The stack s1 is greater than or equal to "
           << "the stack s2." << endl;
   else
      cout << "The stack s1 is less than "
           << "the stack s2." << endl;

   if ( s1>= s3 )
      cout << "The stack s1 is greater than or equal to "
           << "the stack s3." << endl;
   else
      cout << "The stack s1 is less than "
           << "the stack s3." << endl;
}

The stack s1 is less than the stack s2.
The stack s1 is greater than or equal to the stack s3.