int stands for integer (a whole number posotive or negative) Its used for declaring variables with integers. (int d; d = 6;)
while I believe is used for loops for example:
while(blablabla)
{
blablabla
}
or something along those lines
char is short for character (a number or a letter or a symbol) again this is used for declaring variables, except with characters
an actor is a character in your game
and FILE...I have no idea
Anyway, I hope that helps a littl bit