// area2: David I. Schwartz 2/1/2000
// find area and perimeter of circle

import java.text.DecimalFormat;

public class area2 {
    public static void main(String[] args) {
	
	//***************************************************************************
	// Set up TokenReader to obtain input:
	//***************************************************************************
	TokenReader in = new TokenReader(System.in);
	
	//***************************************************************************
	// Choose formula:
	//***************************************************************************
	System.out.print("Enter 1 to compute A. Enter 2 to compute P: ");
	int choice;
	choice = in.readInt();
	if (choice != 1 && choice != 2) {
	    System.err.println("What the hell was that?");
	    System.exit(0);
	}
	// could we have read input better? See "while"
	
	//***************************************************************************
	// Declare variables useful for circle formulas:
	//***************************************************************************
	double radius;
	
	//***************************************************************************
	// Obtain radius:
	//***************************************************************************
	System.out.print("Please enter the radius: ");
	radius = in.readDouble();
	if (radius < 0) {
	    System.err.println("What...are you a loser?");
	    System.err.println("You must enter a positive radius!");
	    System.exit(0);
	}

	//***************************************************************************
	// Report choice to user:
	//***************************************************************************
	System.out.print("\nYou chose to compute ");
	if(choice == 1)
	    System.out.print("area: " + Math.PI*Math.pow(radius,2) + "\n");
	else if(choice == 2)
	    System.out.print("perimeter: " + 2*radius*Math.PI + "\n");
	else {
	    System.err.println("Danger! Something is wrong.");
	    System.exit(0);
	}

	//***************************************************************************
	// Alternative output with formatting:
	//***************************************************************************
	DecimalFormat fmt = new DecimalFormat("0.##"); // 2 decimal places
	System.out.print("\nYou chose to compute ");
	if(choice == 1)
	    System.out.print("area (fancy): " +
			     fmt.format(Math.PI*Math.pow(radius,2)) + "\n");
	else if(choice == 2)
	    System.out.print("perimeter (fancy): " + 
			     fmt.format(2*radius*Math.PI) + "\n");
	else {
	    System.err.println("Danger! Something is wrong.");
	    System.exit(0);
	}


    } // method main

} // class area2