Y’all gonna get tired of seeing me tonight I swear 
Preprocessor Directives: a behind the scenes process that inserts code in your files before the actual code you have written. This extra code can do things like process input/output within the code
Main Function: this is the heartbeat of the program. This is the thing that calls the other things, and essentially processes the program. In game dev, I believe this can be called the “Game Loop”
Expression Statements: These are simply statements that do “something” - whether it be to output on the screen, take in input, etc… These are considered “Expressions” and when you terminate the line with a semicolon, that makes it an “Expression Statement”
Declaration Statements: These are statements that assign values to variables. Or, in longer terms, it specifies an entity by name, and some form of information about the entity, including it’s data type.
Return Statement: This is the line that sends the result of various operations back to the user, OR the function that called it. For example, if I create a function “a” - and it takes in 2 numbers, (num1, num2) and in that function I add num1 + num2, the return would send the result back to whatever called the function