Converts a real number to the string

Submitted by:David Villa

Date added:26 October, 2015


C++ Example code to convert a real number to the string

Tags: convert number , number to string

Code Snippet:

/*$Workfile: KDtoA.c$: implementation file
$Revision: 2$ $Date: 2004-10-08 12:35:49$
$Author: Darko$

Converts a real number to the string.
Copyright: CommonSoft Inc.
Mar 1989 Darko Kolakovic

/* Group=Strings */
/*Note: MS VC/C++ - Disable precompiled headers (/Yu\"StdAfx.h\" option) */

/*Replaces library header file names with the compiler's aliases*/
#ifdef _WIN32
#ifdef _MSC_VER //Micorsoft C++ compiler
#ifdef _UNICODE
#ifndef UNICODE
//To enable Unicode for some Microsoft Visual C/C++ header files,
//the UNICODE definition is required
#define UNICODE
#pragma include_alias(\"KTrace.h\", \"trace.h\")
#pragma include_alias(\"KTChar.h\", \"wtypes.h\")
#endif //_MSC_VER
#endif //_WIN32


#include \"KTrace.h\" /*ASSERT macro */
#include \"KTChar.h\" /*LPCTSTR typedef*/

#ifdef _MSC_VER
/*Microsoft C Compiler*/
#include <stdlib.h> /*_gcvt()*/
#include <float.h> /*DBL_DIG*/

#if _MSC_VER < 1300
/*Microsoft compilers before Visual C++ .Net 2002, 32-bit, version 7.0
expect the users to have set up their own storage

#define _CVTBUFSIZE (309+40) /* Number of digits in maximum double precision
value + slop


/*Converts the given floating-point value to a zero-terminated string.
The supplied buffer should be large enough to accommodate the converted value.
The value includes a decimal point and possiblesign and exponent information,
plus a terminating null character, which is appended automatically.

Returns: a pointer to zero-terminated string. There is no error return.
LPTSTR DtoA(double dValue, /*[in] real number to be converted */
LPTSTR szResult, /*[in] pointer to string buffer */
unsigned int iSize /*[in] size of the resulting buffer in
#ifdef _MSC_VER
/*Microsoft C Compiler*/
char szTemp[_CVTBUFSIZE];

#if !defined _MBCS && !defined _UNICODE
/*Singlebyte-character (SBCS or ASCII) text mapping*/
if (szResult != NULL)
unsigned int i = 0;
_gcvt(dValue, /*value to be converted */
DBL_DIG, /*number of significant digits stored*/
szTemp /*storage location for result */
while ((szTemp[i] != '\0') && (i < iSize))
szResult[i] = szTemp[i];
szResult[i] = '\0';

/*Multibyte-character or Unicode (wide-character) text mapping*/

if (szResult != NULL)

_gcvt(dValue, /*value to be converted */
DBL_DIG,/*number of significant digits stored*/
szTemp /*storage location for result */

/*Convert ANSI string to Unicode*/
MultiByteToWideChar(CP_ACP, /*code page is ANSI*/
0, /*character-type options*/
szTemp, /*string to map*/
strlen(szTemp)+1, /*number of bytes in string*/
szResult, /*wide-character buffer*/
iSize /*size of buffer*/
/*Note: If the MultiByteToWideChar() fails, the return value is zero.
To get extended error information, call GetLastError. GetLastError
may return one of the following error codes:



#endif /* _MSC_VER */

return szResult;

/* ///////////////////////////////////////////////////////////////////////// */
* 3 Biblioteka1.2 8/14/2003 5:00:54 AM Darko Unicode
* 2 Biblioteka1.1 7/16/2002 1:41:15 AM Darko Fixed VSS Log
* tag
* 1 Biblioteka1.0 3/7/2002 5:03:38 PM Darko