Numbers to/from strings

Article Metadata

---

Article

Created: symbianyucca (09 Apr 2007)

Last edited: hamishwillee (25 Jul 2012)

To get numbers out of strings, you can use class called TLex. It can be used for example like this:

_LIT(KtxRemoveUniHex			,”0x”);
 
TInt GetNumberL(const TDesC& aString)
{
	TInt RetNumber(0);
 
	if(aString.Left(2) == KtxRemoveUniHex
	&& aString.Length() > 2)
	{
		TPtrC aString2(aString.Right(aString.Length() - 2));
		TInt err; 
		TLex aLex;
 
		aLex.Assign(aString2);
		User::LeaveIfError(aLex.Val(RetNumber, EHex));
	}
	else
	{
		TLex MyLex(aString);
		User::LeaveIfError(MyLex.Val(RetNumber));
	}
}

As shown in the code with TLex you can also define which numbering system is supposed to be used when converting strings to numbers. Supported numbering systems are:

• EBinary : Binary numbers
• EOctal: Octal numbers
• EDecimal : Decimal numbers
• EHex : Hexadecimal numbers

If you want to put numbers into strings you can use the functions provided by the TDes-class, i.e. Num & AppendNum,:

TInt Numberr(138);
TBuf<200> Buffer;
Buffer.Num(Numberr,EHex)
Buffer.AppendNum(Numberr)

As with TLex you can also define the numbering system used when converting numbers to strings.