getch() : This is a function defined in the file
conio.h and used to get a single character from the keyboard, without displaying it on screen, and no need to press enter after you enter the character.
getche() : This is a function same as
getch(), but the only is that
getche() displays the character you enter on the screen when you hit the button while
getch() doing the same without displaying it on screen. e in
getche() function means echoes means displays. Its prototype is present in
getchar() : getche() is not a function, but it is a macro, present in
stdio.h the file. It is used to get the character from the keyboard after pressing enter.
fgetchar() : fgetchar() is same as
getchar(), the only difference between them is that fgetchar() is a function while getchar() is the macro, both are present in the same file stdio.h