Program to sum input numbers is not working

Question

I am trying to make a program that first takes n inputs from the user, and then calculates the sum of those numbers. Then I want the program to print if the sum is an even or an odd number.

For example if the user types in 3, he/she will have to type in 3 numbers (for example 3, 2, 5): then the program will calculate the sum of those (3 + 2 + 5) and print out if the answer (10) is an odd or an even number.

I thought I coded it right, but it doesn't run in the LMC simulator, can someone please help me finding the error?

My code:

      INP
      STA b
ab    INP
      STA a
      LDA total
      ADD a
      STA total
      STA count
      LDA b
      SUB one
      STA b
      BRZ number
      BRP loop
bc    LDA count
      SUB two
      STA count
      BRZ evennumber
      BRP number
      LDA total
      OUT
      LDA space
      OTC
      OTC
      LDA o
      OTC
      LDA d
      OTC
      OTC
      LDA e
      OTC
      HLT
cd    LDA total
      OUT
      LDA space
      OTC
      OTC
      LDA p
      OTC
      LDA A
      OTC
      LDA r
      OTC
      HLT
a     DAT 0
b     DAT 0
total DAT 0
one   DAT 1
two   DAT 2
count DAT 0
o     DAT 111
space DAT 32
d     DAT 100
e     DAT 101
p     DAT 112
A     DAT 97
r     DAT 114

Answer 1

The main problem in your code is that the labels mismatch.

On the one hand you have defined the following labels:

• ab
• bc
• cd

...but you have referenced the following labels:

• loop
• number
• evennumber

As a consequence your code is not valid ... it will not parse.

The second set of labels make more sense, while "ab", "bc", "cd" are meaningless: they don't help the viewer of your code to understand what they are about. So align your code with the second set.

Also, it is not defined whether LMC is case sensitive, so using a variable name a and another A is not certain to be supported. Instead, give meaningful names. The first a is in fact the number you input and need to add to the sum, so maybe call it summand instead of a. The other A could then be called a, as it really represents the letter "a". b is also meaningless. It represents the number of inputs that are expected, so maybe call it inputs.

Taking that together, your code would look like this:

#input: 2 4 5
        INP
        STA inputs
loop    INP
        STA summand
        LDA total
        ADD summand
        STA total
        STA count
        LDA inputs
        SUB one
        STA inputs
        BRZ number
        BRP loop

number  LDA count
        SUB two
        STA count
        BRZ evennumber
        BRP number
        LDA total
        OUT
        LDA space
        OTC
        OTC
        LDA o
        OTC
        LDA d
        OTC
        OTC
        LDA e
        OTC
        HLT

evennumber LDA total
        OUT
        LDA space
        OTC
        OTC
        LDA p
        OTC
        LDA a
        OTC
        LDA r
        OTC
        HLT

summand DAT 0
inputs  DAT 0
total   DAT 0
one     DAT 1
two     DAT 2
count   DAT 0
o       DAT 111
space   DAT 32
d       DAT 100
e       DAT 101
p       DAT 112
a       DAT 97
r       DAT 114

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