LightOJ 1022 - Circle in Square http://lightoj.com/volume_showproblem.php?problem=1022 水题

LightOJ1022.java

import java.io.BufferedReader;
import java.io.IOError;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.text.DecimalFormat;
import java.util.StringTokenizer;

public class P1022 {

        public void run() {
		Scanner cin = new Scanner(System.in);
		PrintWriter cout = new PrintWriter(new OutputStreamWriter(System.out));

		int test = cin.nextInt();
		double PI = 2 * Math.acos(0.0);
		for (int cas = 1; cas <= test; cas++) {
			cout.print("Case " + cas + ": ");
			double r = cin.nextDouble();
			double s = 4 * r * r - PI * r * r;
			DecimalFormat df = new DecimalFormat("#.00");
	        cout.println(df.format(s));
		}
		
		cout.flush();
	}

	public static void main(String args[]) {
		new P1022().run();
	}

	class Scanner {

		BufferedReader br;
		StringTokenizer st;

		Scanner(InputStream in) {
			br = new BufferedReader(new InputStreamReader(in));
			eat("");
		}

		void eat(String s) {
			st = new StringTokenizer(s);
		}

		String nextLine() {
			try {
				return br.readLine();
			} catch (IOException e) {
				throw new IOError(e);
			}
		}

		boolean hasNext() {
			while (!st.hasMoreTokens()) {
				String s = nextLine();
				if (s == null)
					return false;
				eat(s);
			}
			return true;
		}

		String next() {
			hasNext();
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}
	}

}