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D - toString(double)

reply "Derek Parnell" <Derek.Parnell psyc.ward> writes:
I'm starting to get into D coding in a serious way now. Anyhow, for what  
its worth, here is an alternate 'toString' for doubles. I didn't like the  
way the existing one hides some precision for some values.

Any constructive critisms welcome...

//-------------- toString -----------//
char[] toString(double x)
{
     char[] buffer;
     int l;
     int a;

     // Allocate a big-enough(tm) buffer
     buffer.length = 40;

     // Do the basic formatting into the buffer
     l = sprintf(buffer, "%015.10f", x);

     // Strip off leading zero chars except the one before the decimal.
     for(a=0; (a<l)  && (buffer[a] == '0'); a++){};
     if (buffer[a] == '.')
         a--;

     // Strip off trailing zero chars and any final decimal point if it  
trails.
     for(l--; (l>=0) && (buffer[l] == '0'); l--){};
     if (buffer[l] == '.')
         l--;

     // Return whatever's left.
     return buffer[a..l+1];
}


-- 
Derek
Mar 30 2004
parent Ben Hinkle <bhinkle4 juno.com> writes:
I don't know if it has come up before but yet another nice function
to add to std.string's toString collection would be

char[] toString(Object obj)
{
  if (obj is null)
    return "null";
  else
    return obj.toString();
}

that way you don't have to check if obj is null before toString'ing
it.

More directly related to the original post, how about overloading
toString with formatting inputs like

char[] toString(double x, int precision)
{
// something like Derek's toString or maybe just
// sprintf("%.10g") where 10 is the precision
}

Also maybe it's worth tossing in
char[] toString(double x, char[] format)
{
  char[] buf = new char[40]; // be smarter here
  buf.length = sprintf(buf,format,x);
  return buf;
}

-Ben

On Wed, 31 Mar 2004 15:16:10 +1000, "Derek Parnell"
<Derek.Parnell psyc.ward> wrote:

I'm starting to get into D coding in a serious way now. Anyhow, for what  
its worth, here is an alternate 'toString' for doubles. I didn't like the  
way the existing one hides some precision for some values.

Any constructive critisms welcome...

//-------------- toString -----------//
char[] toString(double x)
{
     char[] buffer;
     int l;
     int a;

     // Allocate a big-enough(tm) buffer
     buffer.length = 40;

     // Do the basic formatting into the buffer
     l = sprintf(buffer, "%015.10f", x);

     // Strip off leading zero chars except the one before the decimal.
     for(a=0; (a<l)  && (buffer[a] == '0'); a++){};
     if (buffer[a] == '.')
         a--;

     // Strip off trailing zero chars and any final decimal point if it  
trails.
     for(l--; (l>=0) && (buffer[l] == '0'); l--){};
     if (buffer[l] == '.')
         l--;

     // Return whatever's left.
     return buffer[a..l+1];
}

Mar 31 2004