public class DatatypesDemo 
{

    public static void main(String[] args)
    {
        // ********************** declaration statements for local variables in the main method
        int num1 = 9;    
        int num2 = 2;
        double num3 = 0;
        // int num4;        // error, can't declare a local primitive variable without 
                            // initializing it to a value such as zero

        int num5 = 0, num6 = 0;     // it is legal to declare & initialize two variables in the same statement 
                                    // but I consider it bad style

        // ********************** assignment statement examples

        num1 = 1000000;	

        // num1 = 4.5;         // error, can't directly assign a decimal number to an int variable
        // num1 = num2 + num3; // error, can't store a decimal value into an int variable even though num3 is zero and num2 + num3 
                               // would work out to a whole number

        // num1 = 3000000000; // error, can't assign a value greater than Integer.MAX_VALUE to an int

        // num1 = 1e6;        // error, using e for exponential notation causes 1e6 to be treated as a double rather than an int

        num3 = 1e6;           // legal to use exponential notation with num3 since it is a double

        // int num1 = 10;     // error, since num1 was already declared as an int in this method & you can't redeclare a variable twice

        // *********************** integer division examples **********************

        num1 = 9;
        num2 = 2; 
        num3 = num1 / num2;   // example of an assignment statement

        System.out.println(num3);     

        // 4.0 (not 4.5) displays due to integer division 
        // even though num3 is a double. The value is immediately truncated as soon as values are divided and before the result
		// is assigned to the variable num3

        

        num1 = 9;
        num2 = 2;
        num3 = (double) num1 / num2;  // example of casting the int variable num1 to a double

        System.out.println(num3);     

        // 4.5 displays since num1 is casted to a double to avoid integer division

        num1 = 9 / 2;                

        System.out.println(num1);

        // 4 displays due to integer division which occurs first before the value is assigned to num1

        num3 = 9. / 2;                

        System.out.println(num3);

        // 4.5 displays since the decimal point after the 9 causes the computer to treat 9. as
        // a double rather than an int value

        // num1 = 8. / 2;   // error, can't directly assign a decimal value into an int variable. Note that 8. / 2 is the double 4. and not the integer 4

        num2 = 1;
        num3 = 2.5;

        num1 = num2 + (int) num3;        // example of casting a double to an int to avoid the error that would occur if not casted

        System.out.println(num1);        // 3 since the casting caused the 2.5 to be truncated to 2

       
        num1 = 0;
        num1 += 2;                    	// using the += compound operator, equivalent to num1 = num1 + 2;

        System.out.println(num1);    	// 2

        num1++;                        	// using the ++ incrementing operator, equivalent to num1 = num1 + 1;
		
        System.out.println(num1);    	// 3

        
        --num1;                        	// using the -- decrementing operator to subtract one

        System.out.println(num1);    	// 2

        

        num1 = Integer.MAX_VALUE;
        System.out.println(num1);       // 2147483647

        //num1 = 2147483648;            // error, since directly assigning a value that overflows int

        num1 = Integer.MAX_VALUE + 1;	// legal since not directly assigning a value to num1 but .....

        System.out.println(num1);       // -2147483648 displays since you wrapped around the number line after integer overflow

        
        num3 = 1e6;                    	// exponential notation

        System.out.println(num3);       // 1000000.0 since 1 x 10^6 = 1 million

        num3 = 1e-2;

        System.out.println(num3);    	// 0.01 since 1 x 10^-2 = 1/100 = one one-hundredth

        

        num3 = 1.0000000000000000002; 

        System.out.println(num3);       // 1.0 due to loss of precision w/ double data type, only about 15 overall digits are accurately stored

        

        num1 = 123;

        System.out.println(num1 % 10);          // 3 one's digit

        System.out.println(num1 % 100 / 10);    // 2 ten's digit

        System.out.println(num1 % 1000 / 100);  // 1 hundred's digit

        

        num3 = 19.99;

        System.out.println(Math.floor(num3));       // 19.0 displays since the floor method truncates the decimal number

        // num1 = Math.sqrt(9);    // error since num1 is int & can't store sqrt of 9 which is 3.0 not 3

        System.out.println(Math.pow(2.5, 2));       // 6.25 which is 2.5 squared

        System.out.println(Math.abs(-3));           // 3 since 3 is the absolute value of -3

        num1 = 2; num2 = 5; num3 = 1;               // it is legal to combine 3 assignment statements on 1 line of code, though I consider it bad style

        System.out.println(Math.max(num1, num2));   // 5 displays since it is the maximum value between num1 (2) and num2 (5)

        int v = 1, w = 4, x = 5, y = 2, z = 3;

        System.out.println(Math.max(Math.max(Math.max(Math.max(v, w), x), y), z));	// 5 displays. This awkward nesting is necessary since Math.max only accepts 2 parameters 

        System.out.println(Math.min(Math.min(num1, num2), num3)); // 1.0

        System.out.println(Math.ceil(1.1));         // 2.0 displays since ceil moves you to the next integer to the right on the number line

        System.out.println(Math.ceil(-1.9));        // -1.0 since ceil moves you to the next integer to the right on the number line

        System.out.println(Math.floor(9.99));       // 9.0 since floor moves you to the next integer to the left on the the number line

        System.out.println(Math.floor(-1.1));       // -2.0 since floor moves you to the next integer to the left on the the number line

        System.out.println(Math.random());          // a random value between [0, 1) such as 0.342

        

        String stringNum = "123";

        System.out.println(stringNum + 1);        // "1231" since Java concatenates when an int and String are "added"

        System.out.println(Integer.parseInt(stringNum) + 1);    // "124" since string value "123" is first converted to numeric value 123.
                                                                // The Integer.parseInt method is similar to the Val and CInt methods in Visual Basic

        stringNum = "123.4";

        System.out.println(Double.parseDouble(stringNum) + 0.1);    // "123.5"

    }

}