Reading data from a given file

Program:

//In this program we are reading the data from a file.
import java.io.*;
public class filer
{
public static void main(String ar[])
{
try
{
FileReader fr=new FileReader("input.txt");
BufferedReader br=new BufferedReader(fr);
String str=br.readLine();
while(str!=null)
{
System.out.println(str);
str=br.readLine();
}

}catch(Exception e)
{
System.out.println(e);
}
}
}
Output:

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Writing data in given file

Program: /*In this program we are writing the data in the file.File will automatically created if there is not a file with the given name*/
import java.io.*;
public class file
{
public static void main(String ar[])
{
try
{
FileWriter fw=new FileWriter("output.txt");
PrintWriter pw=new PrintWriter(fw);
String str="Hello";
String str1="how are you";
pw.println(str);
pw.println(str1);
pw.flush();
pw.close();
fw.close();
}catch(Exception e)
{
System.out.println(e);
}
}
}
Output:
   The data will be written in the given file.

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Java Program Using GUI

Program:

import javax.swing.*;
class sw
{
public static void main(String ar[]) throws Exception
{

int i=10;
int j=20;
JOptionPane.showInputDialog("This is a simple program using GUI");
JOptionPane.showMessageDialog(null,"The sum is:"+(i+j));

}
}
Output:

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Chating program using UDP

Program to chat using UDP Protocol
Server:

import java.io.*;
import java.net.*;
import java.util.*;
class udpchs
{
public static void main(String ar[]) throws Exception
{
DatagramSocket ssoc=new DatagramSocket(3232);
BufferedReader dt=new BufferedReader(new InputStreamReader(System.in));
InetAddress ip=InetAddress.getLocalHost();
byte buf[]=new byte[1024];
DatagramPacket dpac=new DatagramPacket(buf,buf.length);
while(true)
{
ssoc.receive(dpac);
String str1=new String(dpac.getData(),0,dpac.getLength());
System.out.println("Received: "+str1);
String str=new String(dt.readLine());
buf=str.getBytes();
ssoc.send(new DatagramPacket(buf,buf.length,ip,32));
}

}
}
Client:

import java.io.*;
import java.net.*;
import java.util.*;
class udpchc
{
public static void main(String ar[]) throws Exception
{
DatagramSocket ssoc=new DatagramSocket(32);
InetAddress ip=InetAddress.getLocalHost();
BufferedReader dt=new BufferedReader(new InputStreamReader(System.in));
byte buf[]=new byte[1024];
DatagramPacket dpac=new DatagramPacket(buf,buf.length);
//String str=new String(dpac.getData());
while(true)
{
String str=new String(dt.readLine());
buf=str.getBytes();
ssoc.send(new DatagramPacket(buf,buf.length,ip,3232));
ssoc.receive(dpac);
String str2=new String(dpac.getData(),0,dpac.getLength());
System.out.println("Received: "+str2);
}


}

}

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Echo program using UDP

Program to send date using UDP Protocol
Server Code:

import java.io.*;
import java.net.*;
import java.util.*;
class udpehs
{
public static void main(String ar[]) throws Exception
{
String clsent,ssent;
DatagramSocket ssoc=new DatagramSocket(3232);
InetAddress ip=InetAddress.getLocalHost();
clsent=(new Date()).toString();
byte buf[]=clsent.getBytes();
ssoc.send(new DatagramPacket(buf,buf.length,ip,32));


ssoc.close();
}
}
Client code:

import java.io.*;
import java.net.*;
import java.util.*;
class udpehc
{
public static void main(String ar[]) throws Exception
{
DatagramSocket ssoc=new DatagramSocket(32);
byte buf[]=new byte[1024];
DatagramPacket dpack=new DatagramPacket(buf,buf.length);
ssoc.receive(dpack);
String df=new String(dpack.getData());
System.out.println(df);


ssoc.close();
}
}
Output:

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Chating program using TCP

Program for chatting using TCP Protocol
Server Code:

import java.io.*;
import java.net.*;
import java.util.*;
class tcpchs
{
public static void main(String ar[]) throws Exception
{
String clsent,ssent;
ServerSocket wsoc=new ServerSocket(3232);
Socket ssoc=wsoc.accept();
BufferedReader ifc=new BufferedReader(new InputStreamReader(ssoc.getInputStream()));
BufferedReader ifs=new BufferedReader(new InputStreamReader(System.in));
DataOutputStream otc=new DataOutputStream(ssoc.getOutputStream());
while(true)
{
clsent=ifc.readLine();
if(clsent.equals("exit"))
{break;}
System.out.println("From Client: "+clsent);
ssent=ifs.readLine();
otc.writeBytes(ssent+'\n');
}
ssoc.close();
}
}
Client Code:

import java.io.*;
import java.net.*;
import java.util.*;
class tcpchc
{
public static void main(String ar[]) throws Exception
{
String clsent,ssent;
Socket ssoc=new Socket("localhost",3232);
BufferedReader ifs=new BufferedReader(new InputStreamReader(ssoc.getInputStream()));
BufferedReader ifc=new BufferedReader(new InputStreamReader(System.in));
DataOutputStream ots=new DataOutputStream(ssoc.getOutputStream());
while(true)
{
clsent=ifc.readLine();
ots.writeBytes(clsent+'\n');
ssent=ifs.readLine();
if(ssent.equals("exit"))
 break;
System.out.println("From Server: "+ssent);
}
ssoc.close();
}
}
Output for client and server:

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Echo program using TCP

Echo Program using TCP Protocol
Program for Server:

import java.io.*;
import java.net.*;
import java.util.*;
class tcpechos
{
public static void main(String ar[]) throws Exception
{
String csent,ssent;
ServerSocket ss=new ServerSocket(1232);
while(true)
{Socket ws=ss.accept();
BufferedReader infromclient=new BufferedReader(new InputStreamReader(ws.getInputStream()));
DataOutputStream outtoclient=new DataOutputStream(ws.getOutputStream());
csent=infromclient.readLine();
System.out.println("From client: "+csent);
ssent=csent;
outtoclient.writeBytes(ssent+'\n');}
}
}
Program for Client:

import java.io.*;
import java.net.*;
import java.util.*;
class tcpechoc
{
public static void main(String ar[]) throws Exception
{
String csent,ssent;
Socket ws=new Socket("LocalHost",1232);
BufferedReader infromserver=new BufferedReader(new InputStreamReader(ws.getInputStream()));
DataOutputStream outtoserver=new DataOutputStream(ws.getOutputStream());
BufferedReader infromclient=new BufferedReader(new InputStreamReader(System.in));
csent=infromclient.readLine();
outtoserver.writeBytes(csent+'\n');
ssent=infromserver.readLine();
System.out.println("From server: "+ssent);
}
}
Output for client and server:

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Remote Server and Remote Client

Program to use Remote Server and Client programs to run any application
Program for Server:

import java.io.*;
import java.net.*;
import java.util.*;
class rms
{
public static void main(String ar[]) throws Exception
{
String csent,ssent;
ServerSocket ss=new ServerSocket(1234);
Socket soc=ss.accept();
BufferedReader ifs=new BufferedReader(new InputStreamReader(System.in));
BufferedReader ifc=new BufferedReader(new InputStreamReader(soc.getInputStream()));
DataOutputStream otc=new DataOutputStream(soc.getOutputStream());
csent=ifc.readLine();
Runtime h=Runtime.getRuntime();
Process p=h.exec(csent+'\n');
System.out.println("Executed successfully");

}
}

Program for Client:

import java.io.*;
import java.net.*;
import java.util.*;
class rmc
{
public static void main(String ar[]) throws Exception
{
String csent,ssent;
Socket soc=new Socket("localhost",1234);
BufferedReader ifc=new BufferedReader(new InputStreamReader(System.in));
BufferedReader ifs=new BufferedReader(new InputStreamReader(soc.getInputStream()));
DataOutputStream ots=new DataOutputStream(soc.getOutputStream());
System.out.println("Enter the command to be executed");
csent=ifc.readLine();
ots.writeBytes(csent+'\n');
ssent=ifs.readLine();
System.out.println("The command executed successfully");
}
}
Output for client and server:

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Ping Program

Program in java for Ping
Program:

import java.io.*;
import java.net.*;
import java.util.*;
class ping
{
public static void main(String ar[]) throws Exception
{
try{
String str;
BufferedReader buf=new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter the ip address");
String ip=buf.readLine();
Runtime H=Runtime.getRuntime();
Process p=H.exec("ping "+ip);
InputStream in=p.getInputStream();
BufferedReader buf1=new BufferedReader(new InputStreamReader(in));
while((str=buf1.readLine())!=null)
{System.out.println(str);
}}
catch(Exception e)
{System.out.println(e.getMessage());}
}
}
Output:

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Shortest Distance Program

Program to find the shortest distance in the given graph in java.

Program Code:

import java.io.*;

import java.net.*;

import java.util.*;

class dj

{

public static void main(String ar[]) throws Exception

{ int i,j,n,temp,temp1,source,destination,tc,min;

BufferedReader d=new BufferedReader(new InputStreamReader(System.in));

int no[][]=new int[10][10];

System.out.println("Enter the number of nodes");

n=Integer.parseInt(d.readLine());

System.out.println("Enter the transition between the nodes");

for(i=0;i<n;i++)

{

for(j=0;j<n;j++)

{

System.out.print("Cost"+i+"-"+j+"-->");

no[i][j]=Integer.parseInt(d.readLine());

System.out.println();

}

}

System.out.println("Enter the source node");

source =Integer.parseInt(d.readLine());

temp1=source;

System.out.println("Enter the destination node");

destination=Integer.parseInt(d.readLine());

tc=0;

for(i=temp1;i<n;i++)

{min=1000;

for(j=0;j<n;j++)

{

temp=no[i][j];

if(i==j||no[i][j]==0)

continue;

else if(min>temp)

{min=temp;temp1=j;}

else if(temp1==destination)

break;

}

no[temp1][i]=0;

no[i][temp1]=0;

tc=tc+min;

}

if(no[source][destination]!=0)

{if(tc>no[source][destination])

tc=no[source][destination];

}

System.out.println("cost ="+tc);

}

Output:

}

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Intermediate Code Generation

Program to generate intermediate code of any given expression.
Program:

#include<iostream.h>
#include<conio.h>
#include<ctype.h>
main()
{
      int i,k,t,len,b,p,j,c=0,y,o;
      char exp[45],temp[8][50],A[8],stack[8][8];
      char op[10]={'+','*','-','/'};
      char sym[11]={'0','1','2','3','4','5','6','7','8','9'};t=0;j=0;
      cout<<"Enter an  expression\n";
      cin>>exp;
      len=strlen(exp);
      for(i=len;i>=1;i--)
      {
          if(isdigit(exp[i]))
          {
                            while(isdigit(exp[i]))
                            {
                                                 temp[t][i]=exp[i];
                                                 i--;
                                               
                            } exp[i+1]='q';
                            cout<<"After reduction the new expression is  ";
                            for(b=0;b<=i+1;b++)
                            {
                                              cout<<exp[b];
                            }cout<<i<<endl;
          }
          else if(isalpha(exp[i]))
          {
               while(isalpha(exp[i]))
                 {
                    temp[t][i]=exp[i];
                    i--;
                 } exp[i+1]='q';
               
                            cout<<"After reduction the new expression is  ";
                            for(b=0;b<=i+1;b++)
                            {
                                              cout<<exp[b];
                            }cout<<i<<endl;
          }                
         t++;
      }
                                               
      getch();                    
}
Output:

                                      

                                 
                                                                       
                                                                                               

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Implementation of Lexical Analyzer

Program to implement lexical analyzer in c++.
Program:

#include<iostream.h>
#include<conio.h>
#include<ctype.h>
#include<string.h>
main()
{
      int i,j,k,f,len,t;
      char exp[100],word[12][12];
      char op[10]={'+','*','-','/'};
      char key[10][10]={"while","do","else","if"};
      cout<<"Enter the expression\n";
      cin>>exp;
      len=strlen(exp);t=0;
      for(i=0;i<len;i++)
      {
          j=0;f=0;
          if(isalpha(exp[i]))
          {
                            while(isalpha(exp[i])||isdigit(exp[i]))
                            {
                                        word[t][j]=exp[i];
                                        i++;j++;
                            }
                            word[t][j]='\0';
                            i--;
                            for(k=0;k<10;k++)
                            {
                                             if(word[t]==key[k])
                                             {
                                                                cout<<"The "<<word[t]<<" is keyword\n";
                                                                f=1;
                                                                break;
                                             }
                            }
                            if(f==0)
                            {
                                       cout<<"The "<<word[t]<<" is identifier\n";
                            }
          }
          else if(isdigit(exp[i]))
          {
                while(isdigit(exp[i]))
                            {
                                        word[t][j]=exp[i];
                                        i++;j++;
                            }
                            i--;
                            cout<<"The "<<word[t]<<" is constant\n";
          }
          else
          {
              cout<<"The "<<exp[i]<<" is operator\n";
          }
          t++;
      }
      getch();
}    

Output:

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Leading Edges for non terminals

Program to find the leading edge for non terminals present in the grammar production.
Program Code:


#include<iostream.h>
#include<conio.h>
#include<string.h>
main()
{

int n,j,i,k,b;
char pr[10][10],lead[10],temp;
cout<<"Enter the number of production rules you want to enter\n";
cin>>n;
cout<<"Enter the production rules";
for(i=0;i<n;i++)
{
cin>>pr[i];
}int d=0;
for(i=0;i<n;i++)
{d=0;
               for(j=3;j<7;j++)
               {
                                if(islower(pr[i][j]))
                                {
                                                      lead[pr[i][0]]=pr[i][j];
                                                     d=1;
                                                      break;
                                }
                    }
                    if(d==0)
                    {
                   
                      if(lead[pr[i][j]]!='\0')
                      {
                                             lead[pr[i][0]]=lead[pr[i][3]];
                                             break;
                      }
                    }
                   
                       
   }for(i=0;i<n;i++)
    {
                    cout<<"leading["<<pr[i][0]<<"]="<<lead[pr[i][0]]<<endl;
    }    
   getch();
}
                                                   
                                                     

Output:

                                                    

                                                   
                                                     

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Trailing Edges For Productions

Program to find the trailing edge for non terminals present in the grammar production.
Program Code:


#include<iostream.h>
#include<conio.h>
#include<string.h>
#include<ctype.h>
main()
{

int n,j,i,len,l;

char pr[10][10],trail[10];
cout<<"Enter the number of production rules you want to enter\n";
cin>>n;
cout<<"Enter the production rules";
for(i=0;i<n;i++)
{
cin>>pr[i];
}
for(i=0;i<n;i++)
{int d=0;
               for(j=strlen(pr[i]);j>2;j--)
               {
                                if(islower(pr[i][j]))
                                {
                                                      trail[pr[i][0]]=pr[i][j];
                                                      d=1;
                                                      break;
                                }
                     }
                   if(d==0)
                   { while(pr[i][j]!='\0')
                    {l=j;j++;}
                           
                       if(trail[pr[i][j]]!='\0')
                      {
                                             trail[pr[i][0]]=trail[pr[i][l]]
                                             ;
                                             break;
                      }
                    }
                   
                       
   }for(i=0;i<n;i++)
    {
                    cout<<"trailing["<<pr[i][0]<<"]="<<trail[pr[i][0]]<<endl;
    }    
   getch();
}
                                                   
                                                     

Output:

                                                  
                                                     

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Dijkastra's Algorithm

Here is the program to find the shortest path between two nodes using Dijkastra algorithm

import java.io.*;

class MyDijkastra3
{
public static void main(String args[]) throws Exception

{

int n,i,j,tc,temp,current,source,destination,minimum;
int nodes[]=new int[20];
int cost[]=new int[10];
int distance[][]= new int[20][20];
tc=0;temp=0;int f=0;

DataInputStream d = new DataInputStream(System.in);

System.out.println("Enter the number of nodes(max 30)");


n =Integer.parseInt(d.readLine());
System.out.println("Enter the costs to each node(if there is no path between two nodes put distance -1");

for( i=1;i<=n;i++)
{
for(j=1;j<=n;j++)
{

System.out.println("Cost"+i+"-"+j+"-->");

distance[i][j] = Integer.parseInt(d.readLine());

}

}

System.out.println("Enter the source node");
source =Integer.parseInt(d.readLine());

System.out.println("Enter the destination node");
destination=Integer.parseInt(d.readLine());
current=source;
minimum=1000;
for( i=current;i<=n;i++)
{
for(j=1;j<=n;j++)
{ if((i==j )|| (distance[i][j]==-1))
                                                                    {continue;
                                                                     }
else if(minimum>=distance[i][j])
{
minimum= distance[i][j];
current=j;
}
if(current==destination)
{System.out.println("Complete");f=1;
break;

}

}tc=tc+minimum;
minimum=10000;
distance[i][current]=-1;
distance[current][i]=-1;

if(f==1)
{
break;
}

}
if((distance[source][destination]!=0)&&(distance[source][destination]!=-1))
{if(distance[source][destination]<tc)
tc=distance[source][destination];
}


                                  System.out.println("The total min cost from"+ source +"to"+ destination +"is:"+tc);

}}

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