/*Joey Goist
8/26/16
This program will be a review how to start declaring variables in programs. */

public class VariableType {
	public static void main(String[] args) {
		/*What is an identifier
			- It is the variable, parameter, constant, user-defined method, or a defined class.
			- You pick the name.
				- Cannot start with a number or a symbol
				- Cannot be a keyword
				- No spaces
				- It should desribe what the variable represents
				- variables should start with lowercase letter
				- Class name should be capital
				- Use an uppercase letter to seperate two words (getName)
					or use underscore get_name
				- Make it specific (age is different ffrom Age)
				- Do not repeat variable names

		Identifiers have a primitive or built-in type:
			What are the different primitive types:

				INTEGERS:
					byte
					short
					int
					long

				DECIMALS:
					float
					double

				LETTERS/WORDS:
					char
					String

				TRUE/FALSE:
					boolean

		***IMPORTANT AP EXAM: int, double, boolean, String


		If you put in a number too large for an integer you get an overflow error
			Java will give you no warning, you just get a wrong result

		Why should you not always use a long?
			Compile and run time would be faster

		INTIALIZING VARIABLES: */
			int number = 5;
			String word = "hello";
			double decimal = 5.9;

			int x;
			char grade = 'A';
			boolean rerun = false;

			double d = 1.45667E23	//Scientific Notation

		/*CASTING:
			What is casting?
				Converting a data type manually

			Why would you need to use casting?
				We need to watch when dividing. */

			int total = 10, n =3;
			double average = total/n;	//INTEGER DIVISION
			System.out.println(average);

			average = (double)total/n;
			System.out.println(average);

			average = total/(double)n;

			//What would happen here?
			average = (double)(total/n);	//This prints 3.0 based on Order of Operations


		//ASSIGNING/DECLARING VARIABLES
			int sum = 5;
			double tot = sum; //This is allowedsince tot is a double which is larger than an int

			double g = 5.95;
			//int intNum = g;	ERROR: Loss of Precision Error
										//To fix you need to Cast

		//ROUNDING TO WHOLE NUMBERS:
			//We can use Math.round(variableName);
			int negAmount = -5.9;
			System.out.println(Math.round(negAmount));

			//Using the strategy of adding or subtracting .5

			//Math.round returns a double

		/*FINAL VARIABLES:
			What is the final variable?
				- This variable cannot be changed (Constant)
				- Coding etiquette has the name in all caps
				- use _ for two or more words
				- Can declare it or we can delcare and intialize
				- Common use is for array bounds
				- Makes it easier to revise code, by only changing 1 variable */
			final double TAX_RATE = 0.6;
	}
}