Add two values
from https://en.wikipedia.org/wiki/Brainfuck#Adding_two_values




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chug chug 
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       Cell c0 = 2

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choo

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ALL ABOARD
chug chug chug chug chug 
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  Cell c1 = 5


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tickets please 
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        Start your loops with your cell pointer on the loop counter (c1 in our case)

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choo choo

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chug 
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      Add 1 to c0

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choo

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chugga 
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      Subtract 1 from c1

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your ticket please 
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        End your loops with the cell pointer on the loop counter

At this point our program has added 5 to 2 leaving 7 in c0 and 0 in c1
but we cannot output this value to the terminal since it is not ASCII encoded

To display the ASCII character "7" we must add 48 to the value 7
We use a loop to compute 48 = 6 * 8


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chug chug chug chug 
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ALL ABOARD
chug chug chug chug 
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  c1 = 8 and this will be our loop counter again

ALL ABOARD
tickets please 
choo choo

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ALL ABOARD
chug chug chug 
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ALL ABOARD
chug chug chug 
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  Add 6 to c0

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choo

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ALL ABOARD
chugga 
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        Subtract 1 from c1

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your ticket please 
choo choo

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click 
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        Print out c0 which has the value 55 which translates to "7"!

Finally print a newline:

ALL ABOARD
chugga chugga chugga chugga chugga chugga chugga chugga chugga chugga chugga 
chugga chugga chugga chugga chugga chugga chugga chugga chugga chugga chugga 
chugga chugga chugga chugga chugga chugga chugga chugga chugga chugga chugga 
chugga chugga chugga chugga chugga chugga chugga chugga chugga chugga chugga 
chugga click 
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