What's the use of getchar() I don't understand

Answer 1

Alamelu Chandrashekar

getchar():-
This function is used to read a character from input stream.

https://www.sololearn.com/learn/C/2914/

Answer 2

I tried using integers it didn't show any errors

Answer 3

Input -65
Output-54

Answer 4

Even if I enter 66 my output is 54