/* This program demonstrates the use of the Math and Random Libraries in Java.
 * Math is a class available under the java.lang package. It is a static final class, which means it cannot be instantiated.
 * Random is a class available under the java.util package. It is not static, so it has to be instantiated before use.
 * This program only demonstrates a few of the available methods for both classes. Please consult the API for the entire list.
 */
import java.util.Random;
import java.util.Scanner;
class Libraries
{
	public static void main(String [] args)
	{
		Scanner input = new Scanner(System.in);
		//We now use some of the methods in the Math class
		//Finding the absolute value of an integer.
		int num = -20;
		System.out.println("The absolute value of "+num+" is "+ Math.abs(num));
		//Since the Math class is static, we need to refer to the methods using the class name, which is why we say Math.method.
		
		//Finding the absolute value of a double.
		double dnum = -2.873;
		System.out.println("The absolute value of "+dnum+" is "+ Math.abs(dnum));
		
		//Getting the natural logarithm (base e).
		// You can also store the result of the method (its return value) in another variable.
		System.out.println("Enter a double value : ");
		double val = input.nextDouble();
		double logVal = Math.log(val);
		System.out.println("log "+val+" is "+ logVal);

		// To raise a number to a particular power.
		System.out.println("Enter two numbers : ");
		double x = input.nextDouble();
		double y = input.nextDouble();
		double result = Math.pow(x,y);
		System.out.println(x+"^"+y+" is "+result);

		//To use the Random Number Generator, we need to create an object of the Random Class.
		// That sets up a random number generator, which is actually a stream of Random numbers.
		// We can get keep asking the RNG to give us random numbers.

		Random r1 = new Random(); // This uses the current system time as a seed.
		// If we want to specify a seed, we can. Then, we pass the seed in as a parameter.
		// The line would then be: Random r1 = new Random ( 1234);
		// 1234 is the seed we're using.
		
		// To get an integer from the RNG
		int randomNum = r1.nextInt();
		System.out.println("The random number we just got is "+randomNum);
		
		// In case we want to generate an integer in a range with a certain upper limit
		int randomNum1 = r1.nextInt(25);
	
		// That line will generate a number in the range [0,24]. If we want to lower the range, subtract the lower limit. 
		// If you want to raise the range, add the lower limit.
		// For eaxmple, if we wanted to generate a number in the range [1,25], add one to the number generated.

		System.out.println("The new random number, this one in the range [1,25] is "+randomNum1);

		// We can also generate doubles. Doubles generated will always be between 0 and 1. 
		// Also, we cannot specify ranges for doubles.

		double dRandom = r1.nextDouble();
		System.out.println("The random double value we just generated is "+ dRandom);
	}
}