adding digits for integer

I have a small problem.

I want to add digits together but not the integer value.
For example, if the digits are 1, 2, 3. i want d value 123. Or if the value is 12, 30, 15 i want 123015. any suggestions?

Take the digits as strings of single character. Concatenate them using strcat().
Then use atoi() [in C/C++] or CInt() [in VC++]. For converting concatenated string as number.

another way: for example, adding 1 + 2 = 12.
what you need to really do is (1*10) + 2. If you notice, you need to multiply the first number by the 10^(the number of digits in the second number). so you do you get that value? I did it for a project I'm working on by making a function called intpow():



so let's have a look at that line.
while (the_int % i != the_int) i *= 10;
that would be read "if the_int modulus i does not equal the_int, multiply i by 10 and try again until it does."
if you are not familiar with the modulus(%) operator, what it does is perform division but returns only the remainder. so 5 % 2 would be 1.
If you play around with inputting different numbers and mentally walking through my function, you will notice that for a function with x number of digits, the number % 10^x (10 to the power of x) = the number.

if you are still confused, ask more questions and i'll help.