Microsoft KB Archive/157065

= INFO: STL sample for deque: size and deque::resize Functions =

Article ID: 157065

Article Last Modified on 9/17/2003

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APPLIES TO

 The Standard C++ Library, when used with:  Microsoft Visual C++ 4.2 Enterprise Edition

 Microsoft Visual C++ 5.0 Enterprise Edition

 Microsoft Visual C++ 6.0 Enterprise Edition

 Microsoft Visual C++ 4.2 Professional Edition</li></ul>

 Microsoft Visual C++ 5.0 Professional Edition</li></ul>

 Microsoft Visual C++ 6.0 Professional Edition</li></ul>

 Microsoft Visual C++ 6.0 Standard Edition</li></ul>

 Microsoft Visual C++ .NET 2002 Standard Edition</li></ul>

 Microsoft Visual C++ .NET 2003 Standard Edition</li></ul> </li></ul>

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This article was previously published under Q157065

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NOTE: Microsoft Visual C++ NET (2002) supported both the managed code model that is provided by the .NET Framework and the unmanaged native Windows code model. The information in this article applies to unmanaged Visual C++ code only.

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SUMMARY
The sample code below illustrates how to use the deque::size, deque::resize, deque::max_size, deque::end, and deque::begin STL functions in Visual C++.

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Prototype
size_type size const; void resize(size_type n, T x = T); size_type max_size 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 member function size returns the length of the controlled sequence.

The member function resize ensures that size henceforth returns n. If it must make the controlled sequence longer, it appends elements with value x. If no value is supplied, the default value depends upon the type. For example, if it is a deque of chars, the default is a blank. If it is a deque of ints, the default is zero.

The member function max_size returns the length of the longest sequence that the object can control.

Sample Code
////////////////////////////////////////////////////////////////////// // // Compile options needed: -GX // // deque.cpp : // // Functions: // //   size //   resize //   max_size //   begin //   end // // Written by Bobby Mattappally // of Microsoft Product Support Services, // Copyright (c) 1996 Microsoft Corporation. All rights reserved. //////////////////////////////////////////////////////////////////////

/* Compile options needed:-GX
 * 1) include
 * 2) include
 * 1) include

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

typedef deque<char, allocator > CHARDEQUE;

void print_contents (CHARDEQUE deque, char*);

void main

{

//create a with  A, B, C and D    CHARDEQUE  a;    a.push_back('A'); a.push_back('B'); a.push_back('C'); a.push_back('D');

//print out the contents

print_contents (a,"a"); cout <<"max_size of a is " <<a.max_size <<endl; cout <<"size of a is " <<a.size <<endl;

//let us increase the size to 10 // and set the new elements to be 'X'   a.resize(10,'X'); print_contents (a,"a"); cout <<"size of a is " <<a.size <<endl;

//let us resize it to 5

a.resize(5); print_contents (a,"a"); cout <<"size of a is " <<a.size <<endl; cout <<"max_size of a is still " <<a.max_size <<endl;

}

//function to print the contents of deque void print_contents (CHARDEQUE deque, char *name)

{

CHARDEQUE::iterator pdeque;

cout <<"The contents of "<< name <<" : ";

for(pdeque = deque.begin;       pdeque != deque.end;        pdeque++) {       cout << *pdeque <<" " ; }       cout<<endl;

} Program Output is: <pre class="fixed_text">The contents of a : A B C D max_size of a is 4294967295 size of a is 4 The contents of a : A B C D X X X X X X size of a is 10 The contents of a : A B C D X size of a is 5 max_size of a is still 4294967295 NOTE: With Visual C++ 4.2, the max_size value is misleading because a sequence this long cannot be created. See the following Microsoft Knowledge Base article for further information:

160017 BUG: Access Violation Using deque class

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