Adding Strings - function problem

[Tim Astle]

I'm getting a fatal exception when using the following function I wrote.  I
was wondering if any of you guys and gals would notice anything wrong with
it.  I'm not feeling 100% today, so goodness only knows what stupid logic I
wrote into this.

The function "GetDecFromString" just returns a struct from one of the
strings.

All it does it take in 2 strings with periods, converts them to integers,
does the math, and spits out a string result.

Thanks in advance.




// This is my decimal structure
typedef struct
{
     UInt num;
     UInt dec;
} decNum, *decNumPtr;



CharPtr AddDecimals(CharPtr str1, CharPtr str2, UInt places)
{
     // Need to integrate limited decimal places in string
     // Rounding as well...

     decNumPtr dec1, dec2;
     UInt d, result, length;
     int x = 0, i = 0, j = 0;
     CharPtr lstr, strResult;

     // Get Decimal structure from Strings
     dec1 = GetDecFromString(str1);
     dec2 = GetDecFromString(str2);

     // Find difference of decimals
     d = dec1->dec - dec2->dec;

     // Make numbers same length
     if(dec1->dec > dec2->dec)
          while(x < d)
          {
               dec2->num = dec2->num * 10;
               x++;
          }
     else if(dec1->dec < dec2->dec)
          while(x < d)
          {
               dec1->num = dec1->num * 10;
               x++;
          }

     // Add two numbers together
     result = dec1->num + dec2->num;

     // Allocate memory for local string
     lstr = MemPtrNew(sizeof(result));
     // Allocate memory for result string + 1 for decimal
     strResult = MemPtrNew(StrLen(lstr) + 1);

     // Covert UInt to String
     StrIToA(lstr, result);

     // Get String Length
     length = StrLen(lstr);

     // Subtract length result by largest dec value
     // Note:  no need to add 1, because strings start at address 0
     if(dec1->dec > dec2->dec)
          length = length - dec1->dec;
     else
          length = length - dec2->dec;

     // Copy String and insert decimal
     while(lstr[i] != '\0')
     {
          if(i == length)
          {
               strResult[i] = '.';
               i++;
          }
          else
          {
               strResult[i] = lstr[j];
               i++;
               j++;
          }
     }

     // Free memory
     MemPtrFree(lstr);
     MemPtrFree(strResult);

     return(strResult);
}



--

Tim Astle



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