"Concatenating" integers?

Using Arduino Programming Questions
#1

Hey guys, for some odd reason I'm attempting to code an Arduino calculator.

I was doing pretty well I thought, until I hit this small problem. I need to figure out how to add integers onto each other, but not actually add them. For example:

This is what WOULD happen:

int var1 = 2 + 3

Then var1 would = 5

But, instead, I'd want var1 to = those numbers combined, so = 23.

2 + 8 would = 28 etc etc etc

Is there a way to do this?

Cheers,
Dan

#2

Sort of like this?

// input var1
varTotal = (varTotal * 10) + var1;
// have we finished? if not go back to input an other number
#3

Just change the "10" in Mike's example to 2, 8 or 16 (plus a bit of jiggery-pokery with A-F), and you've got yourself the beginnings of a useful programmer's calculator.

#4

Works well, except the integers are in the wrong order.

eg: 123

Comes out as 321.

Thanks for the help.

#5

Works well, except the integers are in the wrong order

You must've entered them in the wrong order.

#6

Derp, stupid error haha. Thanks for the help :slight_smile:

#7

You might want to look up BCD (Binary Coded Decimal) math techniques used by the old 4-bit machines.
It's not as fast but with enough memory you can calculate to arbitrary numbers of digits with total precision.

"It's not as fast" there is a major understatement, btw.

For those who use M$ Windoze, the calculator can be switched to scientific mode and will do hex, dec, oct and bin.

#8

Scientific Mode also includes some Programmer stuff, like Hex/Octal/Binary modes, and Quad-Word, Doouble-Word, Word (INT), Byte

Layed out differently yet again in Vista I've noticed.

#9