INFO: STL sample for deque: size and deque::resize Functions (157065)
The information in this article applies to:
- The Standard C++ Library, when used with:
- Microsoft Visual C++, 32-bit Enterprise Edition 4.2
- Microsoft Visual C++, 32-bit Enterprise Edition 5.0
- Microsoft Visual C++, 32-bit Enterprise Edition 6.0
- Microsoft Visual C++, 32-bit Professional Edition 4.2
- Microsoft Visual C++, 32-bit Professional Edition 5.0
- Microsoft Visual C++, 32-bit Professional Edition 6.0
- Microsoft Visual C++, 32-bit Learning Edition 6.0
- Microsoft Visual C++ .NET (2002)
- Microsoft Visual C++ .NET (2003)
This article was previously published under Q157065 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. 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++. MORE INFORMATIONRequired Header
<deque>
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
*/
#include <iostream>
#include <deque>
#if _MSC_VER > 1020 // if VC++ version is > 4.2
using namespace std; // std c++ libs implemented in std
#endif
typedef deque<char, allocator<char> > 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:
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
REFERENCES Visual C++ Books On Line: Visual C++ Books:C/C++:Standard
C++ Library Reference.
Modification Type: | Major | Last Reviewed: | 9/17/2003 |
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Keywords: | kbcode kbinfo KB157065 |
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