How to check that numbers "a" and " b", a digit at a position "i" from number "b" is less or equal than the digit at position "i" at number "a"?

Question

How to check that for given natural numbers "a" and " b", a digit at a position "i" from number "b" is less than the digit at position "i" at number "a" without iterating digit by digit?

e.g.

for :

a = 22222

b = 10001 is ok but b= 10030 is not ok.

I know that in case digits are less or equal then the subtraction can be done without "borrowing" but how can I validate if a subtraction was done with "borrowing" or not ?

Answer 1

use mod function followed by integer division and comparison. For example if you want to compare 22222 and 10030 at the position where the 3 occurs, first take mod100mod100 so you have 22 and 30. Next integer divide by 10 (ignore the remainders) so now you have 2 and 3. Compare them >> by Mirko