// DoublesAsApproximates.java

class DoublesAsApproximates {
	
	public static void main(String[] args) {
		
		System.out.println("This program demonstrates some problems with doubles");
		System.out.println("in Java.  In particular, they only give APPROXIMATE");
		System.out.println("answers.  These are VERY CLOSE (within, say, 10^-10)");
		System.out.println("but still NOT EXACT!");
		System.out.println("Here are some examples:");

		System.out.println();
		System.out.print("The square root of 2 times itself = ");
		System.out.println(Math.sqrt(2) * Math.sqrt(2));

		System.out.println();
		System.out.print("sin(pi) = ");
		System.out.println(Math.sin(Math.PI));

		System.out.println();
		System.out.println("Caveat Emptor!!!");
		System.out.println();

	}
	
	///////////////////////////////////
	// readString, readInt, readDouble
	///////////////////////////////////
	
	public static String readString() {
		java.io.InputStreamReader isr = new java.io.InputStreamReader(System.in);
		java.io.BufferedReader d = new java.io.BufferedReader(isr);
		try { return d.readLine(); } catch (Exception e) { return "error"; }
	}
	public static int readInt() { return Integer.parseInt(readString()); }
	public static double readDouble() {
		return Double.valueOf(readString()).doubleValue();
	}
}