You can not create a number with arbitrary upper and lower limits. It is common in the C language to create an integer comprised of 16 bits. Such an integer has a minimum of:
-(2^15) = -32768
...and maximum of:
(2^15) - 1 = +32767
Instead, after pressing the positive button, consider testing if "total_value" is 5 and skipping adding 1 to "total_value" if TRUE. Conversely, after pressing the negative button, consider testing if "total_value" is -5 and skipping subtracting 1 from "total_value" if TRUE.