How to use the basic_string size and resize Standard Template Library (STL) functions in Visual C++ (157433)


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 Professional Edition 4.2
    • Microsoft Visual C++, 32-bit Professional Edition 5.0
    • Microsoft Visual C++ .NET (2002)
    • Microsoft Visual C++ .NET (2003)
This article was previously published under Q157433
Note Microsoft Visual C++ .NET 2002 and Microsoft Visual C++ .NET 2003 support both the managed code model that is provided by the Microsoft .NET Framework and the unmanaged native Microsoft Windows code model. The information in this article applies only to unmanaged Visual C++ code.

SUMMARY

The sample code below illustrates how to use the basic_string size() and resize() STL function(s) in Visual C++.

MORE INFORMATION

Required header

   <string>

Prototype

   size_type size() const;

   void resize(size_type n, E c = E());
				
   resize is defined in header xstring which is included indirectly.
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 size() function returns the length of the sequence.

The resize() function changes the size to the length specified by the first parameter. If the sequence is made longer, the function appends elements with the value of the second parameter. This value defaults to a null. The output of the sample code shows spaces for the null characters. operator<< reads the size of string and outputs each character in the string one at a time.

Sample code

////////////////////////////////////////////////////////////////////// 
// 
// Compile options needed: /GX
// 
// <filename> :  size.cpp
// 
// Functions:
// 
//    size()
//    resize() ; Defined in header xstring which is included indirectly.
// 
// Written by Linda Koontz
// of Microsoft Product Support Services,
// Copyright (c) 1996 Microsoft Corporation. All rights reserved.
////////////////////////////////////////////////////////////////////// 

#include <iostream>
#include <string>

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

void main()
{

    string TestString = "1111122222333334444455555";
    cout << TestString << "\n  size: " << TestString.size() << endl;
    TestString.resize(5);
    cout << TestString << "\n  size: " << TestString.size() << endl;
    TestString.resize(10);
    cout << TestString << "\n  size: " << TestString.size() << endl;
    TestString.resize(15,'6');
    cout << TestString << "\n  size: " << TestString.size() << endl;

}
Output is: 
1111122222333334444455555
  size: 25
11111
  size: 5
11111
  size: 10
11111     66666
  size: 15

REFERENCES

For more information about basic_string size and resize, visit the following Microsoft Developer Network (MSDN) Web site:

http://msdn.microsoft.com/library/en-us/vclang98/html/sample_basic_string_size_and_resize_(STL_Sample).asp?frame=true

Modification Type:MajorLast Reviewed:7/13/2005
Keywords:kbhowto kbfunctions kbcode kbinfo kbSTL kbtemplate KB157433 kbAudDeveloper
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