Digit problems

Use non-negative integers within the exact integer range. MOD 10 extracts the last digit; DIV 10 removes it. See digits of a number.

Count even digits, including zero#

1n = 40722x = n3count = 04IF x == 0 THEN5  count = 16END7WHILE x > 08  IF (x MOD 10) MOD 2 == 0 THEN9    count = count + 110  END11  x = x DIV 1012END13PRINT count

The result is 3: digits 4, 0, 2. For n = 0, the answer is 1 because zero is written with one even digit. Without the separate case, the loop would never run and the count would remain zero.

Check a numeric palindrome#

1n = 12212x = n3reversed = 04WHILE x > 05  reversed = reversed * 10 + x MOD 106  x = x DIV 107END8PRINT reversed9PRINT n == reversed

The output is 1221, then TRUE. For 120, the numeric reversal is 21 and the check gives FALSE. For 0, expect 0, then TRUE. Numbers do not preserve leading zeros; use text and the string palindrome example for identifiers such as "00100".

Try it#

Test 7, 20, 135, 2002. Predict each result before running. To accept negative inputs, first decide whether the sign should be ignored, then explicitly use ABS(n).