Microsoft KB Archive/142493

= BUG: Cannot Cast Double to int for Use in an Array Declarator =

Article ID: 142493

Article Last Modified on 7/5/2005

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APPLIES TO


 * Microsoft Visual C++ 4.0 Professional Edition
 * Microsoft Visual C++ 4.1 Subscription
 * Microsoft Visual C++ 4.2 Professional Edition
 * Microsoft Visual C++ 4.2 Enterprise Edition
 * Microsoft Visual C++ 5.0 Learning Edition
 * Microsoft Visual C++ 5.0 Learning Edition
 * Microsoft Visual C++ 5.0 Enterprise Edition
 * Microsoft Visual C++ 5.0 Professional Edition

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This article was previously published under Q142493



SYMPTOMS
The compiler generates the following error when you type cast a 'const float' or 'const double' to 'const int' in an array declarator:

error C2057: expected constant expression



RESOLUTION
To work around this problem, use a #defined double value in place of a const double. See the "Workaround Sample Code" section for an example.



STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.



Sample Code to Demonstrate Problem
/* Compile options needed: /c */

const double d_max = 5.55; int arr[(const int) d_max];  // Gives C2057 here

// The following code also gives the error: const double d_max = 5.55; const int imax = (const int) d_max;

int arr[imax];  // Gives C2057 here

Workaround One - Sample Code
#define D_MAX 5.55 const int imax = (const int) D_MAX; int arr[imax];

Workaround Two - Sample Code
#define D_MAX 5.55 int arr[(const int) D_MAX];

Additional query words: kbVC400bug

Keywords: kbbug kbcpponly kbcompiler KB142493

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