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• Implicit Type Conversions - part 2
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Here is the program for converting a 64bit integer to string/char */ascii..
Please let me know any issues, suggestions..

//Converts a 64bit integer to a string
bool i64toa( int64 value, char * buf, int maxLen)
{
  int lsbByte = 0;
  char tempchr[10];
  char tmpchar;
  int count = 0;
  int bufLen = 0;
  bool negValue = false;
  int cnt = -1;

  if ((buf == NULL ) || ( maxLen == 0 ))
  {
    return false;
  }

  memset(buf, 0, maxLen );
  memset(tempchar, 0x00, sizeof(tempchar));

  if( value == 0 )
  {
    buf[0] = '0';
    return true;
  }

  //If its a negative integer, convert it to positive and continue
  if( value < 0 )
  {
    value = -value;
    negValue = true;
    buf[0] = '-';
    buf++;
    bufLen++;
  }

  //Extract byte by byte starting from the least significant byte
  //of the 8 byte integerand form a string . The output string
  //will contain the integer in the format least significant byte
  //to most significant byte
  while (value)
  {
    if ( bufLen++ > maxLen )
    {
      return false;
    }

    lsbByte = (int8)( value % 10 ) ;
    value = value/10;

    cnt = snprintf( tempchr, sizeof(tempchr),”%d”, abs(lsbByte) );
    if ( ( cnt < 0 ) || ( cnt >= (int)sizeof(tempchr) ) )
    {
      return false;
    }

    strcat(buf, tempchr);
    memset(tempchar, 0×00, sizeof(tempchar));
  } 

  if (negValue)
  {
    bufLen–;
  }

  //Reverse the string to get the format most significant byte to
  //least significant byte
  for (count = 0; (count < (bufLen/2)); count++)
  {
    if (((bufLen - count - 1) < maxLen) &&
        (count < maxLen))
    {
      tmpchar = buf[count];
      buf[count] = buf [bufLen-count-1];
      buf[bufLen-count-1] = tmpchar;
    }
    else
    {
      return false;
    }
  }

  return true;
} 

Download the source code i64toa.txt

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Related Blog Items

• String to Integer (atoi)
• Convert integer to binary string
• Unsigned long to string (ultostr)
• Implicit Type Conversions - part 2
• Unsigned long long (uint64) to string (ulltostr)

This entry was written by openasthra and posted on December 4, 2007 at 9:05 pm and filed under C Tidbits. Bookmark the permalink. Follow any comments here with the RSS feed for this post. Both comments and trackbacks are currently closed.