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Q158037: STL Sample for the stack::operator== Function

Article: Q158037
Product(s): Microsoft C Compiler
Version(s): 4.2,5.0,6.0
Operating System(s): 
Keyword(s): kbcode kbVC420 kbVC500 kbVC600 kbDSupport
Last Modified: 17-APR-2002

-------------------------------------------------------------------------------
The information in this article applies to:

- The Standard C++ Library, used with:
   - Microsoft Visual C++, 32-bit Enterprise Edition, versions 4.2, 5.0, 6.0 
   - Microsoft Visual C++, 32-bit Professional Edition, versions 4.2, 5.0, 6.0 
   - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
-------------------------------------------------------------------------------

SUMMARY
=======

The sample code below illustrates how to use the stack::operator== STL function
in Visual C++.

MORE INFORMATION
================

Required Header
---------------

     <stack>

Prototype
---------

     template<class _TYPE, class _C, class _A>
     bool stack::bool operator==(const stack<_TYPE, _C, _A>& _X) const;

NOTE: The class/parameter names in the prototype may not match the version in the
header file. Some have been modified to improve readability.

Description
-----------

The stack::operator== function returns true if both stacks have equal elements
arranged in the same sequence. The stack::operator== function always returns
false if the two stacks are of different size.

Sample Code
-----------

  ////////////////////////////////////////////////////////////////////// 
  // 
  // Compile options needed: /GX
  // 
  // StackEqual.cpp :  Illustrates how to use the stack::operator==
  //                   function to determine if two stacks are equal.
  // 
  // Functions:
  // 
  //    operator== :  Returns true if both stacks are the same.
  // 
  // Written by Derek Jamison
  // of Microsoft Product Support Services,
  // Copyright (c) 1996 Microsoft Corporation. All rights reserved.
  ////////////////////////////////////////////////////////////////////// 

  #pragma warning(disable:4786)

  #include <stack>
  #include <iostream>
  using namespace std;

  #if _MSC_VER > 1020   // if VC++ version is > 4.2
     using namespace std;  // std c++ libs implemented in std
     #endif

  typedef stack<double, deque<double, allocator<double> >,

             allocator<double> > STACK_DOUBLE;

  void main()

  {

     STACK_DOUBLE stack1,stack2;

     // Add item 4.0 to Stack1.
     cout << "stack1.push(4.0)  s1=[4.0]" << endl;
     stack1.push(4.0);

     // Add item 3.0 to Stack1. Current Stack1 contains items 3.0 (top)
     // 4.0 (bottom).
     cout << "stack1.push(3.0)  s1=[3.0 4.0]" << endl;
     stack1.push(3.0);

     // Add item 4.0 to Stack2.
     cout << "stack2.push(4.0)  s2=[4.0]" << endl;
     stack2.push(4.0);

     // Compare Stack1 and Stack2. Should return False.
     cout << "stack1==stack2 is " <<
        ((stack1==stack2)? "True": "False") << endl << endl;

     // Add item 6.0 to Stack2. Current Stack2 contains items 6.0 (top)
     // 4.0 (bottom)
     cout << "stack2.push(6.0)  s2=[6.0 4.0]" << endl;
     stack2.push(6.0);

     // Compare Stack1 and Stack2. Should return False.
     cout << "stack1==stack2 is " <<
        ((stack1==stack2)? "True": "False") << endl << endl;

     // Keep adding item 8.0 to Stack2. Current Stack2 contains items
     // 8.0 (top), 6.0 and 4.0 (bottom).
     cout << "stack2.push(8.0)  s2=[8.0 6.0 4.0]" << endl;
     stack2.push(8.0);

     // Compare Stack1 and Stack2. Should return False.
     cout << "stack1==stack2 is " <<
        ((stack1==stack2)? "True": "False") << endl << endl;

     // Delete the top item from Stack2. Current Stack2 contains items
     // 6.0 (top) and 4.0 (bottom).
     cout << "stack2.pop()      s2=[6.0 4.0]" << endl;
     stack2.pop();

     // Delete another item from Stack2. Current Stack2 contains item 4.0.
     cout << "stack2.pop()      s2=[4.0]" << endl;
     stack2.pop();

     // Add item 3.0 to Stack2. Current Stack2 contains item 3.0 (top) and
     // 4.0 (bottom).
     cout << "stack2.push(3.0)  s2=[3.0 4.0]" << endl;
     stack2.push(3.0);

     // Compare Stack2 and Stack2. Should return True.
     cout << "stack1==stack2 is " <<
        ((stack1==stack2)? "True": "False") << endl << endl;

     // Delete the top item from Stack2. Current Stack2 contains 4.0.
     cout << "stack2.pop()      s2=[4.0]" << endl;
     stack2.pop();

     // Delete another item from Stack2. Stack2 should be empty.
     cout << "stack2.pop()      s2=[]" << endl;
     stack2.pop();

     // Push item 8.0 to Stack2.
     cout << "stack2.push(8.0)  s2=[8.0]" << endl;
     stack2.push(8.0);

     // Compare Stack1 and Stack2. Should return False.
     cout << "stack1==stack2 is " <<
        ((stack1==stack2)? "True": "False") << endl << endl;

  }

Program Output
--------------

  stack1.push(4.0)  s1=[4.0]
  stack1.push(3.0)  s1=[3.0 4.0]
  stack2.push(4.0)  s2=[4.0]
  stack1==stack2 is False

  stack2.push(6.0)  s2=[6.0 4.0]
  stack1==stack2 is False

  stack2.push(8.0)  s2=[8.0 6.0 4.0]
  stack1==stack2 is False

  stack2.pop()      s2=[6.0 4.0]
  stack2.pop()      s2=[4.0]
  stack2.push(3.0)  s2=[3.0 4.0]
  stack1==stack2 is True

  stack2.pop()      s2=[4.0]
  stack2.pop()      s2=[]
  stack2.push(8.0)  s2=[8.0]
  stack1==stack2 is False

REFERENCES
==========

Visual C++ Books On Line: Visual C++ Books:C/C++:Standard C++ Library Reference.

Additional query words: STL STLSample operator==

======================================================================
Keywords          : kbcode kbVC420 kbVC500 kbVC600 kbDSupport 
Technology        : kbVCsearch kbAudDeveloper kbVCLibrary
Version           : :4.2,5.0,6.0
Issue type        : kbinfo

=============================================================================

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