#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;

//type use long
typedef long TYPE;

bool rcmp (const TYPE &a,const TYPE &b)
{
	return a>b;
}

//An vector for global, would keep at most k elements
vector<TYPE> vec;
TYPE k;

int main () {

	k = 100;

	TYPE e;

	while(cin>>e) {
		vec.push_back(e);
	}

	//sort from big to small
	sort(vec.begin(), vec.end(), rcmp);

	cout << "Final top " << k << endl;
	for (unsigned i=0; i<k && i<vec.size(); i++) {
		cout << vec[i] << endl;
	}

	return 0;
}

select title from books where title like '%n_x%'  #可以匹配标题linux或者unix

select * from books, publishers where books.publisher_id = publisher.publisher_id

update books set price = price - 5.00 where title like '%c++%'  #全部的c++书减价5块

delete from books where title like '%c++%'  #删除所有c++的书

insert into books values('A guide to java', '0-33-4-22-5555', 0, 45.5)  #必须逐项对应books的每个字段

create table books
(
  title CHAR(50),
  ISBN CHAR(50),
  id int(10),
  price decimal(10,2)
)

import java.io.*;
import java.net.*;
import java.util.*;

public class SocketTest {
    public static void main(String [] args) {
        Socket socket = null;
        try {
            socket = new Socket("time.nist.gov", 13);

            InputStream in = socket.getInputStream();
            Scanner scan = new Scanner(in);
            while(scan.hasNextLine()) {
                String line = scan.nextLine();
                System.out.println(line);
            }
        } catch(Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if(socket!=null) {
                    socket.close();
                }
            } catch(Exception e1) {
            }
        }   

    }
}

socket.setSoTimeout(2*1000);

Socket socket  = new Socket();
socket.connect(xxx, 2*1000);

import java.net.*;

public class DNSTest {
    public static void main(String [] args) throws Exception {
        InetAddress addrs[] = InetAddress.getAllByName("www.google.com");
        for(int i=0; i<addrs.length; i++) {
            System.out.println(addrs[i].getHostAddress());
        }
    }
}

74.125.71.106
74.125.71.147
74.125.71.99
74.125.71.103
74.125.71.104
74.125.71.105

InetAddress addr = InetAddress.getLocalHost();

import java.util.*;
import java.net.*;
import java.io.*;

public class EchoServer {
    public static void main(String [] args) {
        try {
            ServerSocket server = new ServerSocket(8888);

            byte [] buf = new byte[1024];
            int len = 0;
            while(true) {
                Socket client = server.accept(); // accept client
                try {
                    InputStream in = client.getInputStream();
                    OutputStream out = client.getOutputStream();

                    while((len = in.read(buf, 0, 1024))!=-1) {
                        out.write(buf, 0, len);
                    }
                } catch(Exception e1) {
                    e1.printStackTrace();
                } finally {
                    if(client!=null) {
                        client.close();
                    }
                }
            }
        } catch(Exception e) {
            e.printStackTrace();
        }
    }
}

import java.util.*;
import java.net.*;
import java.io.*;

class ThreadEchoHandler implements Runnable {

	public ThreadEchoHandler(Socket socket) {
		this.socket = socket;
	}

	public void run() {
		byte [] buf = new byte[1024];
		int len = 0;
		try {
			InputStream in = socket.getInputStream();
			OutputStream out = socket.getOutputStream();
			while((len = in.read(buf, 0, 1024))!=-1) {
				out.write(buf, 0, len);
			}
		} catch(Exception e1) {
			e1.printStackTrace();
		} finally {
			try {
				socket.close();
			} catch(Exception e) {
			}
		}
	}

	private Socket socket;
}

public class ThreadEchoServer {
	public static void main(String [] args) {
		try {
			ServerSocket server = new ServerSocket(8888);

			while(true) {
				Socket client = server.accept(); // accept client
				Thread t = new Thread(new ThreadEchoHandler(client)); //new thread
				t.start();
			}
		} catch(Exception e) {
			e.printStackTrace();
		}
	}
}

Socket socket = new Socket("127.0.0.1", 8080);
OutputStream output = socket.getOutputStream();
while(true)
{
    out.write(...);
}
socket.shutdownOutput();   //半关闭！
while(..)
{
    in.read(...);
}
socket.close();

SocketChannel channel = SocketChannel.open(new InetSocketAddress(host, port));
OutputStrem out = Channels.newOutputStream(channel);

import java.net.*;
import java.io.*;
import java.util.*;

public class URLTest {
    public static void main(String [] args) throws Exception {
        URL url = new URL("http://www.ict.ac.cn");
        URLConnection conn = url.openConnection();
        InputStream in = conn.getInputStream();
        StringBuilder sb = new StringBuilder();
        byte [] buf = new byte[1024];
        int len;
        while(( len = in.read(buf, 0, 1024))!=-1) {
            sb.append(new String(buf, 0, len));
        }
        System.out.println(sb.toString());
        Map<String,List<String>> header_map = conn.getHeaderFields();
        for(String key:header_map.keySet()) {
            System.out.println(key+" = "+header_map.get(key));
        }
    }
}

public void setRequestProperty(String key,
                      String value);

import java.net.*;
import java.io.*;
import java.util.*;

public class PostTest {
    public static void main(String [] args) throws Exception {
        //POST DATA key & value
        URL url = new URL("http://www.coder4.com/post.php");
        URLConnection conn = url.openConnection();
        conn.setDoOutput(true);
        PrintWriter writer = new PrintWriter(conn.getOutputStream());
        writer.print("post_key=");
        writer.println(URLEncoder.encode("这是一段POST数据", "UTF-8"));
        writer.close();

        //Input
        InputStream in = conn.getInputStream();
        StringBuilder sb = new StringBuilder();
        byte [] buf = new byte[1024];
        int len;
        while(( len = in.read(buf, 0, 1024))!=-1) {
            sb.append(new String(buf, 0, len));
        }
        System.out.println(sb.toString());
        Map<String,List<String>> header_map = conn.getHeaderFields();
        for(String key:header_map.keySet()) {
            System.out.println(key+" = "+header_map.get(key));
        }
        in.close();
    }
}

<configuration>
  <title></title>
  ......
</configuration>

<font>
    <family>宋体</family>
    <size>14</size>
</font>

<font size="14" family="宋体">
</font>

//构造DocumentBuilderFactory实例
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
//构造DocumentBuilder实例
DocumentBuilder builder = factory.newDocumentBuilder();
//用DocumentBuilder解析文档
Document doc = builder.parse("./test.xml");

import javax.xml.parsers.*;
import org.w3c.dom.*;
import org.xml.sax.*;
import java.io.*;

public class XMLTest {
    public static void main(String [] args) throws
        Exception {
            DocumentBuilderFactory factory =
                DocumentBuilderFactory.newInstance();
            DocumentBuilder builder =
                factory.newDocumentBuilder();
            Document doc = builder.parse("./sitemap.xml");

            //Get root element
            Element root = doc.getDocumentElement();
            //Get all children
            NodeList nodes =  root.getChildNodes();
            for(int i = 0; i < nodes.getLength(); i++) {
                Node node = nodes.item(i);
                if(node instanceof Element) {
                    System.out.println("Element "+node.getNodeName());
                    NamedNodeMap attr_map = node.getAttributes();
                    for(int j=0;j<attr_map.getLength();j++) {
                        Node node_attr = attr_map.item(j);
                        if(node_attr instanceof Attr) {
                            System.out.println(((Attr)node_attr).getName() + " " + ((Attr)node_attr).getValue());
                        }
                    }
                } else if (node instanceof Text) {
                    System.out.println("Text "+node.getNodeName());
                    System.out.println(((Text)node).getWholeText().trim());
                    System.out.println();
                } else {
                    System.out.println(node.getClass());
                }
            }
        }
}

<?xml version="1.0" ?>
<!DOCTYPE configuration SYSTEM "http://www.xxx.com/config.dtd"

<configuration>
    <database>
        <user>user</user>
        <pass>123456</pass>
    </database>
</configuration>

import javax.xml.parsers.*;
import javax.xml.xpath.*;
import org.w3c.dom.*;
import org.xml.sax.*;
import java.io.*;

public class TestXPath {
    public static void main(String [] args) throws Exception {
        //doc
        DocumentBuilderFactory factory =
            DocumentBuilderFactory.newInstance();
        DocumentBuilder builder =
            factory.newDocumentBuilder();
        Document doc = builder.parse("./sitemap.xml");
        //Xpath
        XPathFactory xpath_factory = XPathFactory.newInstance();
        XPath path = xpath_factory.newXPath();

        //XPath visit as Text
        String text = path.evaluate("/urlset/url[1]/loc", doc);
        System.out.println(text);

        //XPath visit as Node
        Node node = (Node)path.evaluate("/urlset/url[1]", doc, XPathConstants.NODE);
        System.out.println(node.getNodeName());

        //XPath visit as Number(as double)
        Double num = (Double)path.evaluate("/urlset/url[1]/priority", doc, XPathConstants.NUMBER);
        System.out.println(num);

    }
}

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
......
</xsd:schema>

import org.xml.sax.helpers.*;
import javax.xml.parsers.*;
import org.xml.sax.*;

public class SAXTest {
    public static void main(String [] args) throws Exception {
        //SAXParser
        SAXParserFactory sax_fac = SAXParserFactory.newInstance();
        SAXParser sax_parser = sax_fac.newSAXParser();

        //Handler
        DefaultHandler handler = new DefaultHandler()
        {
            public void startElement(String uri, String localName, String qName, Attributes attributes) {
                for(int i = 0; i < attributes.getLength(); i++) {
                    String name = attributes.getLocalName(i);
                    if(name.equals("href")) {
                        String value = attributes.getValue(i);
                        System.out.println(value);
                    }
                }
            }
        };  

        //SAXParser
        sax_parser.parse("./sitemap.xml", handler);
    }
}

import org.xml.sax.helpers.*;
import javax.xml.parsers.*;
import javax.xml.stream.*;
import org.xml.sax.*;
import java.io.*;

public class StAXTest {
    public static void main(String [] args) throws Exception {
        //StAXParser
        XMLInputFactory stax_fac = XMLInputFactory.newInstance();
        XMLStreamReader parser = stax_fac.createXMLStreamReader(new FileReader("./sitemap.xml"));

        //Use reader to pull all event
        while(parser.hasNext()) {
            int event = parser.next();
            if(event==XMLStreamConstants.START_ELEMENT) {
                int attr_cnt = parser.getAttributeCount();
                if(attr_cnt!=0) {
                    for(int i=0;i<attr_cnt; i++) {
                        String attr_name = parser.getAttributeLocalName(i);
                        if(attr_name.equals("href")) {
                            System.out.println(parser.getAttributeValue(i));
                        }
                    }
                }
            }
        }   

    }
}

//创建子结点
Document doc = builder.newDocument();
Element rootElement = doc.createElement("root");
doc.appendChild(rootElement);

//添加Text
Text textNode = doc.createTextNode("I'm text string.");
rootElement.appendChild(textNode);

//设置属性
rootElement.setAttribute(name, value);

import org.xml.sax.helpers.*;
import javax.xml.parsers.*;
import javax.xml.stream.*;
import org.xml.sax.*;
import java.io.*;

public class WriteXMLTest {
    public static void main(String [] args) throws Exception {
        //StAXParser
        XMLOutputFactory stax_fac = XMLOutputFactory.newInstance();
        XMLStreamWriter writer = stax_fac.createXMLStreamWriter(new FileWriter("./temp.xml"));

        //Make document
        writer.writeStartDocument();
        //make root node
        writer.writeStartElement("root");
        //make node1 node and attribute
        writer.writeStartElement("node1");
        writer.writeAttribute("attr", "attr_value");
        writer.writeEndElement();
        writer.writeEndElement();
        writer.writeEndDocument();
        //Flush to disk
        writer.close();
    }   
}