Starting function breakout in example_4.cpp

Broke out input_validation_numbers & user_guess_boundaries from main function to seperate functions to test nesting and function chaining.
Interim input validation functions
Small edits on input_validation_numbers function

Trying to use a function to validate input and then pass the validated input (numbers only, within 0-100 range) back to the main function for hints and program exit.
Improve input_validation loop

Outstanding issues:
(1) When a valid guess is entered, it passes the first check, but does not enter into the if statement, or return properly to the main function. Exact issue unknown at this time.
Slight improvement in ln 38 while loop.

Issue may continue to be with parens () in line 38, and/or lack of proper placement of !.
Fix indents & spacing
Fix indent in ln 41, update ln 38 while loop parens and !
Fix for "or" as it should be "||"

In trying to eliminate the issues with this update, I have commented out a few lines/sections in order to assist in troubleshooting.
Remove superfluous while loop and bool

Also fix for intent in line 37
Switch to using do/while and if/else if loops.

Program properly handles number output that is < 0 or > 100.
Program properly handles letters.
Program will not properly handle numbers among 0-100.
Fix for else/if loops.

Program now properly handles good input. Had to move the block of code which handled proper input above the block which handled if something bad (non numbers) was entered.
Remove extra diag lines for good_input.