c arrays

tba

I'm pretty new at this lark so beg your pardon if this is a simple question, I just can't figure out what to google for a procedure.

I want to add the digits of a variable ie.

1234 is the variable so; 1+2+3+4=10

I assume an array is the best way to approach this am I completely on the wrong track? Any tips or quick links suggestions would be most welcome.

satchmo

Well you could either..
(a) Convert the number to a string - aka an array of chars (there are lib functions to do this) - and then just convert each character to a number and sum, or
(b) Observe that for an integer x, the digit at place n is (x/(10^n))%10, where n=0 denotes the least significant digit. Loop over the digits and sum the result.

The first solution is pretty hacky - you shouldn't have to use strings to work out numeric stuff like this - but it also doesn't limit the length of the number to the size of the datatype used to store it, which the second method does.

Webmonkey

Obviously you mean the variable value you want to add as you can't have variable names starting with numbers in C.

You could keep getting toe modulo 10 of the number.

sum = 0
num = 1234

while (num >= 0)
do
[b]num % 10[/b] // = 4 - add this integer value to sum.
[b]num = num / 10[/b] // = 123 - set this integer value to num
endwhile

if you trouble codeing this puedocode let me know.

Think that should work.

Edit - just noticed probably similer to satchmo 2nd method.