There is a universal algorithm for evaluating numbers written in any positional numeral system. Once you know the base and can convert each symbol into its corresponding digit, the algorithm is simply:
result = result * base + digit;
Suppose you are reading a number in base 10 say 1234:
Let's decompose in exponentials from left to right:
1234 = 1*10³ + 2*10² + 3*10¹ + 4*10⁰
Now we factor 10:
10(1*10² +2*10¹+3)+4
And again:
10(10(1*10+2)+3)+4
Finally:
10(10(10(1) +2)+3+4
Alternatively:
((1×10+2)×10+3)×10+4
This works for any positional numeral system. Changing 2 to 10 parses decimal numbers, changing it to 16 parses hexadecimal numbers (after converting A–F to 10–15) and so on.
