help in c language

[patner]

assalamoalikum koi bhai mujhe printf(); clrscr(); getch(); putchar puts gets cin<< cout>> ki definition bata dain plz english main yeh definition mujhe yad krni hain board k papers k liye plz jo ap ko best definition lagain wo bata dain

[Kashif Mehmood1]

printf and cout are used to dislplay some data on the output screen to user
scanf and cin are used to get input from user .
clrscr is used to clear the outputs creen,
getch is used to get a single character from user, it halt the screen until the user press a key from keyboard.

[patner]

putchar gets ki definition nahi hai bhai