MQLII questions

 
Hello all :)
I'm trying to convert MQLII code tou MQL4 code, but I have some questions about:

// MQLII code
Var : MyCondition(False);
Vars : MyValue(1.2345);
Variable : Counter(0);
Variable : String("");
Variables : String1("Some string");
Variables : Counter(0);

- What is the difference between these syntaxes: Var, Vars, Variable and Variables ???
- Can I declare Integer, Double, String or Boolean using all of these Keywords ?
- And how can I know the data type of these variables like "Counter" is it Integer, Double ?

Big thanks if you can explain me this syntax.
Yousky
Reason: