public class datatypes 
{
    public static void main(String[] args)
    {
        // declaration statements
        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;	
        // this 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 truncated immediately
        // as soon as values are divided.
        
        num1 = 9;
        num2 = 2;
        num3 = (double) num1 / num2;
        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 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 = 9. / 2;   // error, can't directly assign a decimal value into an int variable
        
        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
        System.out.println(num1);       // -2147483648 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
        // 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
        num1 = 2; num2 = 5; num3 = 1;
        System.out.println(Math.max(num1, 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  
        System.out.println(Math.min(Math.min(num1, num2), num3)); // 1.0
        System.out.println(Math.ceil(1.1));         // 2.0
        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
        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)
        
        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
        stringNum = "123.4";
        System.out.println(Double.parseDouble(stringNum) + 0.1);    // "123.5"
    }
}