/* This program serves as a demonstration for methods and method overloading.
 * Method overloading is the process of having many methods with the same name, that differ in aspects like return type and number, 
 * type and order of arguments.
 */
import java.util.Scanner;
class Overloading
{
	//This method returns the area of a circle, given its radius.
	static double circleArea (double radius)
	{
		//We are not required to store the result of the calculation in a variable. We can just return it directly.
		//In this case, the value is calculated first, and then returned.
		return Math.PI*radius*radius;
	}

	//This method returns the volume of a sphere, given its radius
	static double volumeOfSphere (double r)
	{
		return 4.0/3.0*Math.PI*Math.pow(r,3);
	}
	
	//This method returns the surface area of a solid hemisphere.
	static double surfaceArea (double rad)
	{
		return 3*Math.PI*rad*rad;
	}

	/* This method prints the calculated information. 
	 * We read in the radius in this method, instead of passing it in from a calling method.
	 * This is a print method, so the return type is void. It also doesn't require any parameters, since we accept input here.
	 */
	static void print()
	{
		// We need to declare a new Scanner for every method that does user input.
		Scanner input = new Scanner (System.in);
		System.out.print("Enter the radius: ");
		double radius = input.nextDouble();
		System.out.println("The area os the circle is "+circleArea(radius)
				   	+ "\nThe voulme of the sphere is "+volumeOfSphere(radius)
					+ "\nThe surface area of the hemisphere is "+surfaceArea(radius));
	}

	/* This method demonstrates both method overloading and a method with default parameters.
	 * This method is also called "print" and prints a triangle. 
 	 * Since this is also a print method, its return type is the same as the previous method.
	 * We differentiate it from the previous method by having it accept a parameters
	 */
	static void print (char symbol, int numLines, boolean isHorizontal )
	{
		if(isHorizontal)// This prints a horizontal triangle, that points to the right.
		{
			if(numLines%2==0)
			{
				System.out.println("The horizontal triangle cannot have even number of lines. Reducing line count by 1.");
				numLines--;
			}
			for(int i=0;i<=numLines/2;i++)
			{
				for(int j =0;j<=i;j++)
					System.out.print(symbol+" ");
				System.out.println();
			}
			for(int i=0;i<numLines/2;i++)
			{
				for(int j=0;j<numLines/2-i;j++)
					System.out.print(symbol+" ");
				System.out.println();
			}
		}
		else	// This prints a vertical triangle, pointing up.
		{
			for(int i=0;i<numLines;i++)
			{
				//This for loop takes care of the preceding spaces in each line.
				for(int j=0;j<numLines-i-1;j++)
					System.out.print(" ");
				//This for loop prints the required number of characters in each line.
				for(int k=0;k<=i;k++)
					System.out.print(symbol+" ");
				//We are done with a line. Moving on to the next one.
				System.out.println();
			}
		}
	}
	public static void main(String [] args)
	{
		// If we ant to print the information about the spherical structures, we just call the print() method.
		print();
		
		//If we want to print the triangles, we call the print method, along with parameters.		
		print('*',5,false);	// We can write code to have the user input these values. But, this is just a demonstration.
	}
}