These are graphical functions. So, when you are using GUI as windows you use following functions:
clrscr() - Clear the screen
getch() - get a single character from input stream
and gotoxy() is a very special function in windows like GUI, it is used to send a user on a particular position of a screen.
When we divide screen horizontally (i.e. left to right or vice versa) we say it is divided in rows and when its in vertical (i.e. top to bottom or vice versa) format it is column.
To place cursor on a particular row+column gotoxy() is used.