Please explain it

How to do this without using ascii code?

using ascii code is the actuall way to do this question , alternative way is to use stl functions like isupper() and islower() ,present in cctype header file ,which are boolean function which tells us whether the character is uppercase or lowercase .
you can check some examples here :- https://www.geeksforgeeks.org/isupper-islower-application-c/

but this is not something i would recommend

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