Microsoft KB Archive/170199

= HOWTO: STL Sample for slice::(length, start, stride) Functions =

Article ID: 170199

Article Last Modified on 12/2/2003

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APPLIES TO

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

 Microsoft Visual C++ 4.2 Professional Edition

 Microsoft Visual C++ 5.0 Enterprise Edition

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

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

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

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

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This article was previously published under Q170199

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SUMMARY
The sample code below illustrates how to use the slice::length, slice::start, and slice::stride STL functions in Visual C++.

Note that there are some differences in the implementation of the Standard C++ Library components in Visual C++ version 4.2 versus later revisions. The relevant sections of code below compile conditionally based upon the value of _MSC_VER.

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Prototype
class slice {  public:

slice; slice(size_t st, size_t len, size_t str); size_t start const;

#if _MSC_VER == 1020 // version 4.2 - declare length

size_t length const;

#else // later than version 4.2, length changed to size

size_t size const;

#endif

size_t stride 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
This sample demonstrates the use of STL slice array to change "Hello World!" string to "Hello There." string.

Sample Code
//////////////////////////////////////////////////////////////////////    //     // Compile options needed: None //    // :  main.cpp //    // Functions: //    //  slice::length, slice::start, slice::stride //    // Written by Yeong-Kah Tam // of Microsoft Product Support Services, // Copyright (c) 1996 Microsoft Corporation. All rights reserved. //////////////////////////////////////////////////////////////////////

#include            // for i/o functions #include            // for valarray using namespace std;

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

void main {      // Initialize string 1 to contain "Hello World!", // and string 2 to contain "There". valarray string1("Hello World!", 12); valarray string2("There.", 6);

// Display both strings. cout << "String 1 = "; int strlen; #if _MSC_VER == 1020  // version 4.2 - call length strlen = string1.length; #else  // later than 4.2 - call size strlen = string1.size; #endif for (int i = 0; i < strlen; i++) cout << string1[i]; cout << "\r\n";

cout << "String 2 = "; #if _MSC_VER == 1020  // version 4.2 - call length strlen = string2.length; #else  // later than 4.2 - call size strlen = string2.size; #endif for (i = 0; i < strlen; i++) cout << string2[i]; cout << "\r\n\r\n";

// slice(6, 6, 1) creates a slice array of      //{6, 7, 8, 9, 10, 11} which is used to select // the elements of string1. "World!" it is. In      // turn, these elements are replaced by the corresponding // element in string2. slice slice_obj(6, 6, 1); string1[slice_obj] = string2;

// Display starting index, length, // and stride of the slice object. cout << "slice - starting index = " << slice_obj.start; cout << "\r\n"; #if _MSC_VER == 1020  // version 4.2 - call length cout << "slice - length = " << slice_obj.length << "\r\n"; #else  // later than 4.2 - call size cout << "slice - length = " << slice_obj.size << "\r\n"; #endif cout << "slice - stride = " << slice_obj.stride << "\r\n"; cout << "\r\n";

// Now print out the result. cout << "After the change, String 1 = "; #if _MSC_VER == 1020  // version 4.2 - call length strlen = string1.length; #else  // later than 4.2 - call size strlen = string1.size; #endif for(i = 0; i < strlen; i++) cout << string1[i]; cout << "\r\n"; }

Program Output
<pre class="fixed_text">  String 1 = Hello World! String 2 = There.

slice - starting index = 6 slice - length = 6 slice - stride = 1 After the change, String 1 = Hello There.

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