DOCUMENT:Q158203  29-APR-2002  [visualc]
TITLE   :STL Sample for the string::operation
PRODUCT :Microsoft C Compiler
PROD/VER::4.2,5.0,6.0
OPER/SYS:
KEYWORDS:kbcode kbVC420 kbVC500 kbVC600 kbDSupport

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

 - The Standard C++ Library, included 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 
    - Microsoft Visual C++.NET (2002) 
-------------------------------------------------------------------------------

SUMMARY
=======

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

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

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

      <string>

Prototype
---------

      Function 1:
         template<class _E, class _TYPE, class _A> inline
         bool operator<=(const basic_string<_E, _TYPE, _A>& LString,
                         const _E *RCharArray);

      Function 2:
         template<class _E, class _TYPE, class _A> inline
         bool operator<=(const _E * LCharArray,
                         const basic_string<_E, _TYPE, _A>& RString);

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
-----------

There are two versions of the string::operator<= function. Both versions are
used to compare a null-terminated character array to a basic_string. They
perform this operation by negating the result of (RString<LCharArray or
RCharArray<LString). For more information on this comparison, please see the
string::operator< function.

Note that this operator does not work with NULL pointer for the character array.
You will need to make sure that the character array is not NULL before you pass
it to the operator.

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

   ///////////////////////////////////////////////////////////////////////// 
   // 
   // Compile options needed: /GX
   // 
   // StringLessEqual.cpp : Illustrates how to use the operator<= to compare
   //                       a basic_string variable to a null-terminated
   //                       string.
   // 
   // Functions:
   // 
   //    operator<=   Returns true if the second parameter is not less
   //                 than the first.
   // 
   // Written by Derek Jamison
   // of Microsoft Product Support Services,
   // Copyright (c) 1996 Microsoft Corporation. All rights reserved.
   ///////////////////////////////////////////////////////////////////////// 

   #pragma warning(disable:4786)

   #include <string>
   #include <iostream><BR/>
   using namespace std;

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

   void trueFalse(int x)

   {
     cout << (x? "True": "False") << endl;
   }

   void main()

   {

      string S1="DEF";
      char CP1[]="ABC";
      char CP2[]="DEF";
      char CP3[]="DEFG";
      char CP4[]="def";

      cout << "S1 is " << S1 << endl;
      cout << "CP1 is " << CP1 << endl;
      cout << "CP2 is " << CP2 << endl;
      cout << "CP3 is " << CP3 << endl;
      cout << "CP4 is " << CP4 << endl;

      cout << "S1<=CP1 returned ";
      trueFalse(S1<=CP1);  // False  (calls function 1)

      cout << "S1<=CP2 returned ";
      trueFalse(S1<=CP2);  // True   (calls function 1)

      cout << "S1<=CP3 returned ";
      trueFalse(S1<=CP3);  // True   (calls function 1)

      cout << "CP1<=S1 returned ";
      trueFalse(CP1<=S1);  // True   (calls function 2)

      cout << "CP2<=S1 returned ";
      trueFalse(CP2<=S1);  // True   (calls function 2)

      cout << "CP4<=S1 returned ";
      trueFalse(CP4<=S1);  // False   (calls function 2)

   }

Program Output is:

   S1 is DEF
   CP1 is ABC
   CP2 is DEF
   CP3 is DEFG
   CP4 is def
   S1<=CP1 returned False
   S1<=CP2 returned True
   S1<=CP3 returned True
   CP1<=S1 returned True
   CP2<=S1 returned True
   CP4<=S1 returned False

REFERENCES
==========

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

Additional query words: STL STLSample operator string

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

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2002.