How create an Little Mans Computer (LMC) code that will get a number. Display 1 if the number is odd, display 0 if the number is even

Question

I need help in my study\'s where it can display 1 if the number is even and 0 if the number is odd. for example if the input is 99 it will display the output 1 which means odd.

Answer 1

It is possible to tell odd and even numbers apart by doing a division through repeated subtractions.
In general, a number is even if it is divisible by two, or in more pragmatic terms if the rest of the division by two is zero¹.

To divide b by a we can simply subtract a from b and repeat until the freshly updated b is less than a.
The number of times we looped is the number b/a, the value left in b is the reminder b mod a.
We are interested in the latter, so we won't count the number of iterations.

Input b
While b >= 2 Do
   b = b - 2
End While

If b == 0 Then
   Output 1;
Else
   Output 0;
End If

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Unfortunately, LMC doesn't have a compare with immediate instruction.
This is not a problem however as we can rewrite b >= 2 as b - 2 >= 0 which is something closer to what LMC can do.
But b - 2 is the same computation done in the loop, so we can reuse that entirely

Input b
Do
   b = b - 2
Loop While b >= 0
b = b + 2

Output b

The b = b + 2 is needed because on exit from the loop b is negative, it is either -1 (if the number was odd) or -2 (if the number was even). That's why I added the equal sign to the loop condition.
By adding 2 we can then directly output b.

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The algorithm above compute the complement of your problem, it outputs 0 for even numbers and 1 for odd ones.
I silently added this "twist" so that a dumb copy-paste will harm you.

Since it is a homework, I leave the task of inverting the output to your self.

The code is below, hidden.
Please, note that this code doesn't solve the original exercise, using it as it will get you a zero.

INP                       ;ACC = Number from user
sub2_loop

  SUB two                 ;ACC = ACC - 2

BRP sub2_loop             ;If ACC >= 0, keep subtracting 2

 ;ACC < 0, since we were subtracting 2 ACC can only be -1 or -2

 ADD two                  ;Set ACC = 1 or 0

end
 OUT                      ;Show ACC
 HLT

 two DAT 2

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¹ Usually programmers take advantage of the base two properties (namely that 2⁰ is the only odd power of two) but that requires an AND or a SHIFT operation to extract to least binary digit.
LMC doesn't have either and doesn't even natively works with binary numbers, so we need to emulate a division.