Give numbers an explicit size

# Problem Description

Users are reporting different limits of the program's memory usage as well as the maximum values that are supported.

Currently, we are using `int` which typically are at least 32 bit, but depend on the C++ implementation.

# Desired Behavior

Update the program so it uses the `int32_t` data type to force all builds to have the consistent limit.

The acceptable numbers should be displayed to the user after the welcome message, using the line of output:

`(Limited to whole numbers between -2,147,483,648 and 2,147,483,647)`