De bai:Giai pt bac 2 client -UDP

//UDP2C.java import java.io.*; import java.net.*; class UDP2C{ public static void main(String[] args) { DatagramSocket cl=null; BufferedReader key=null; byte[] inBuff,outBuff; DatagramPacket indata,outdata; String s,a,b,c; String ipserver="localhost"; int pserver=8000; //begin try{ cl=new DatagramSocket(); key=new BufferedReader( new InputStreamReader(System.in)); System.out.print("a="); a=key.readLine().trim(); System.out.print("b="); b=key.readLine().trim(); System.out.print("c="); c=key.readLine().trim(); s=a+" "+b+" "+c; outBuff=s.getBytes(); outdata=new DatagramPacket(outBuff, outBuff.length, InetAddress.getByName(ipserver), pserver); cl.send(outdata); inBuff=new byte[1024]; indata=new DatagramPacket(inBuff,inBuff.length); cl.receive(indata); s=new String(indata.getData()); System.out.println("Ket qua:"+s); } catch(IOException e) { System.out.println(e); } finally { if(cl!=null) cl=null; } } }

//UDPB2S.java import java.net.*; import java.io.*; import java.util.*; class UDPB2S{ static String gptb2(double a,double b,double c) { String s=""; double delta=b*b-4*a*c; if(delta<0) s="Phuong trinh vo nghiem"; if(delta==0) { s="Phuong trinh co nghiem kep x1=x2="+(-b/(2*a)); } if(delta>0) { s="Phuong trinh co 2 nghiem phan biet:x1="+((-b+Math.sqrt(delta))/(2*a))+"; x2="+((-b-Math.sqrt(delta))/(2*a)); } return s; } public static void main(String[] args) { DatagramSocket svr=null; Socket cl=null; byte[] inBuff,outBuff; DatagramPacket indata,outdata; int pserver=8000; String s; double a,b,c; try{ svr=new DatagramSocket(pserver); inBuff=new byte[1024]; indata=new DatagramPacket(inBuff,inBuff.length); svr.receive(indata); InetAddress addrclient=indata.getAddress(); int pclient=indata.getPort(); s=new String(indata.getData()); StringTokenizer stk=new StringTokenizer(s); a=Double.parseDouble(stk.nextToken().trim()); b=Double.parseDouble(stk.nextToken().trim()); c=Double.parseDouble(stk.nextToken().trim()); s=gptb2(a,b,c); System.out.println("Ket qua:"+s); outBuff=s.getBytes(); outdata=new DatagramPacket(outBuff, outBuff.length,addrclient,pclient); svr.send(outdata); } catch(IOException e) { System.out.println(e); } finally{ if(svr!=null) svr=null; } } }