varandprimdatatypes

package lessons;

public class VariablesAndPrimitiveDataTypes
{

	public static void main(String[] args)
	{
		//(int)egers = 3 (can hold up to about 2 billion)
		//floating point numbers(32bit) /doubles(64bit) = 1.17 |+-3.4^38
		//bytes = 0-128 (only whole numbers)
		//short = 0 - 32 767
		//boolean = true or false
		//chars= single characters
		//long = +-2^63
//largest to smallest: double,float,long,int,short,byte,char,boolean

		//dataType variableName
		// variable declaration
		byte inches;
		short month;
		int speed;
		long lightYear;
		float salesCommission;
		double distance;


		System.out.println("Example 1: Integer Data Types");
		int checking;
		byte miles;
		short minutes;
		long days;
		//the types of data these can hold are whole numbers ONLY


		//variable initialization
		checking = -20;
		miles = 105;
		minutes = 120;
		days = 189_000;

		// + are catination operations. It means to join together.
		System.out.println("we have a journey of "+ miles + " miles.");
		System.out.println("it took us " + minutes + " minutes");
		System.out.println("Our account balance is $"+ checking);
		System.out.println("About " + days + " days ago, Columbus"+" stood on this spot.");

		int length, width, area;
		int number = 1_257_649;

		System.out.println("\n Example 2: Floating Point Data Types");

		double price, tax, total;

		price = 29.75;
		tax = 1.76;
		total = 31.51;

		System.out.println("The price of the item is " +price);
		System.out.println("The tax is "+ tax);
		System.out.println("The total is " + total);

		float numberA;
		numberA = 23.5F;

		System.out.println("\nExample 3: E Notation");

		double distanceB, mass;
		distanceB = 1.495979E11;
		// E = times ten to the power of
		mass = 1.989E30;

		System.out.println("The sun is " + distanceB + " meters away");
		System.out.println("the suns mass is " + mass + " kilograms.");

		System.out.println("\n ex4 boolean data type");

		boolean bool;
		bool = true;
		System.out.println(bool);
		bool = false;
		System.out.println(bool);

		System.out.println("\nEx5 stringls and string concatenation");

		//strings are complex objects, a string of characters
		//'myVar' is an object
		String myVar = "Hello World";
		System.out.println(myVar);

		String greeting ="hello how are you ";
		String name = "mitchell";
		System.out.println(greeting + name);


		System.out.println("peter piper picked a packe of peppers. "
				+ "if peter pirper had pickeled a pack "
				+ "of peppers how many pepppeers have peres pcik ");

		System.out.println("Ex6 Char data type");

		char letter;
		// ALL CHAR MUST BE enclosed in SINGLE quotes, double would be a string
		letter = 'A';
		System.out.println(letter);
		letter = 'b';
		System.out.println(letter);

		System.out.println("Ex7 Variables hold only one value at a time");
		int unitsSold;
		//when naming variable use a lowercase first words can be capital

		int lengthA = 20;
		// int is java reserved word, lengthA is user def word, 20 is numerical literal
		//when stating equivalent variables the var with a value must be right side
		int metersB = lengthA;

		int flightNum = 69, travelTime, departure = 10, destination;
		//four var declared only two initialized

		int x =5;
		System.out.println(x);
		x = 6;
		System.out.println(x);

		int myNum;
		int myNUM;
		int mYnum;
		// all these variables are different because of use of capital and lowercase
		//variables cannot contain spaces, instead use '_' ex. my_name
		//Variables cannot START with an number
		//Variables cannot contain symbols ECXEPT a $ sign, ex.
		 int $num = 15; //this is ok









	}

}