Check out http://www.davidbray.org/palm/dtostr.html and
http://www.davidbray.org/palm/strtod.html
The functions are strToDouble and doubleToStr - I got the name wrong from
memory.
The functions I use - quite successfully - are based on David's algorithms.
I include them here:
----------------------------------------------------------------------------
------
/**
* Convert double value to C string. The string can have up to 9
* fractional digits (digits after decimal). Sufficient space must
* be provided to store the resulting string - 20 bytes of storage is
* recommended.
*
* @param str pointer to storage for the resulting string data.
* @param flpNumber the floating point (double) number to be converted to
* an ascii string.
* @param numFractDigits max number of digits to be included after the
* decimal point. If less than the actual number of fraction digits
* in the number, the value will be rounded up to specified number
* of fraction digits.
* @param fixedFractDigits true (the default value) if the specified number
* of fraction digits are to be generated, false if trailing zero digits
* are to be trimmed from the string representation of the number.
* @return the callers storage buffer pointer (str).
*
*/
char* doubleToStr(char* str, double flpNumber, int numFractDigits,
Boolean fixedFractDigits) {
long longNumber;
double flpIP, zeros, round;
int i, remainder, strLen;
char sign = ' ';
if(numFractDigits < 0)
numFractDigits = -numFractDigits;
if(numFractDigits > 9)
numFractDigits = 9;
if (flpNumber < 0.0)
{ flpNumber = -flpNumber;
sign = '-';
}
zeros = 1.0;
for (i=0; i<numFractDigits; i++)
zeros *= 10;
round = 0.51/zeros;
flpNumber += round;
flpIP = (Int32) flpNumber;
flpNumber = flpNumber - flpIP;
// REC remove addition of annoying leading space on postive number
if(sign == '-') {
str[0] = sign;
StrIToA(&str[1], (Int32) flpIP);
}
else {
StrIToA(str, (Int32) flpIP);
}
strLen = StrLen(str); // put in the decimal point and terminate the
string
//Remove annoying decimal point when no fractions requested
if(numFractDigits > 0) {
str[strLen] = '.';
str[numFractDigits+strLen+1] = '\0';
strLen++;
}
longNumber = flpNumber * zeros; // fractional part
for (i=numFractDigits+(strLen-1); i>(strLen-1); i--) // convert the
integer part
{ remainder = longNumber % 10;
str[i] = remainder + 0x30;
longNumber /= 10;
}
if(!fixedFractDigits && numFractDigits > 0) {
// trim any trailing zero digits
int pos = StrLen(str) - 1;
for(; numFractDigits > 0;
pos--, numFractDigits--) {
if(str[pos] == '0')
str[pos] = '\0';
else
break;
}
if(!numFractDigits)
str[pos] = '\0'; // get rid of decimal
}
return str;
}
// Routine to convert a string to a double -- Allowed input is in fixed
notation ddd.fff
//
double strToDouble(char* str)
{ int i, start, length, punctPos;
double result, sign, fractPart;
//UInt16 attributes;
if(str == 0 || *str == 0)
return 0.0;
result = fractPart = 0.0;
length = punctPos = StrLen(str);
// REC - skip any leading whitespace
for(start = 0; str[start] != '\0' && TxtCharIsSpace(str[start]); start++)
; // intentional null statement
sign = 1.0;
if (str[0] == '-') {
sign = -1.0;
start++;
}
for (i=start; i<length; i++) { // parse the string from left to right
converting the integer part
if (str[i] != '.') {
if (TxtCharIsDigit(str[i]))
result = result * 10.0 + (str[i] - 0x30);
else
return 0.0;
}
else {
punctPos = i;
break;
}
}
if (str[punctPos] == '.') { // parse the string from the end to the '.'
converting the fractional part
for (i=length-1; i>punctPos; i--) {
if (TxtCharIsDigit(str[i]))
fractPart = fractPart / 10.0 + (str[i] - 0x30);
else
return 0.0;
}
result += fractPart / 10.0;
}
return result * sign; // correcting the sign
}
----------------------------------------------------------------------------
------
Cheers,
Ralph
"David Orriss Jr" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Ralph Curtis wrote:
> > Seems that most people use MathLib for intensive floating point work.
Also
> > provides trig functions. You might also search the archives for
> > DoubleToString and StringToDouble algorithms that people have posted a
> > number of times.
> >
> >
>
> I managed to find a version of DoubleToString in the archives, but not
> StringToDouble... oh well.. Thanks.
>
> --
> DavidO
>
> My blog: http://mywebpages.comcast.net/daorriss/
> My PalmOS apps:
>
http://www.palmgear.com/index.cfm?fuseaction=software.developer&userID=82264
6423
>
>
--
For information on using the Palm Developer Forums, or to unsubscribe, please
see http://www.palmos.com/dev/support/forums/
