method to find sum of digits of a number until sum becomes single digit
def digSum ( n ) : NEW_LINE INDENT sum = 0 NEW_LINE while ( n > 0 or sum > 9 ) : NEW_LINE INDENT if ( n == 0 ) : NEW_LINE INDENT n = sum NEW_LINE sum = 0 NEW_LINE DEDENT sum += n % 10 NEW_LINE n /= 10 NEW_LINE DEDENT return sum NEW_LINE DEDENT