Iterating through an Object Array

package edu.training.object;

public class ArrayObject {

      public static void main(String[] args) {

     

            Object[] myObjects = {

                        new Integer(12),

                        new String("foo"),

                        new Integer(5),

                        new Boolean(true)

            };

           

            for (Object o: myObjects) {

                  System.out.println(o);

                 

            }

      }

}

Output:

12

foo

5

true

Code to sort an array of 0's and 1's efficiently

package org.training.algo;

public class SortZeroAndOne {

      public static void main(String args[]) {

           

            int array[] = {0,1,1,1,0,0,0,0,0,1,0,0,1,0,1,1,1,0,0,0,0,0,0,0,1,0,1,0,1,1};

            int numberOfOnes = 0;

           

            for (int i = 0 ; i < array.length; i++)

            {

                  // adding all the elements in the array, the result would be the number of ones in the array

                   numberOfOnes += array[i];

            }

           

            // subtract the number of ones from the length of the array to get the number of zeros in the array

            int numberOfZeros = array.length - numberOfOnes;

           

            System.out.println("Length of Array: "+ array.length);

            System.out.println("Number of Zeros: "+ numberOfZeros);

            System.out.println("Number of Ones: "+ numberOfOnes);

           

            for ( int i = 0; i < array.length; i++)

            {

                  // one reached the number of zeros start filling the array with one's

                  if (i >= numberOfZeros)

                  {

                        array[i] = 1;

                  }

                  else

                        // fill the first half with zeros

                        array[i] = 0;

            }

           

            for ( int i = 0; i < array.length; i++)

            {

                  System.out.print(array[i]+",");

            }

      }

}

Output:

Length of Array: 30

Number of Zeros: 18

Number of Ones: 12

0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,

Understanding Maps

package edu.scjp.maps;

import java.util.HashMap;

import java.util.Map;

public class MapProgram {

     

      public static void main(String args[]) {

           

            Map credentials = new HashMap();

           

            credentials.put("a160097", "sridhariyer");

            credentials.put("a160093", "sridhariyer");

            credentials.put("a160092", "sridhariyer");

            credentials.put("a160091", "sridhariyer");

            credentials.put("a160097", "sridhariyer");           

           

            System.out.println(credentials.keySet());

           

            System.out.println(credentials.entrySet());

           

            for (String key : credentials.keySet()) {

                  System.out.println("Values: "+ credentials.get(key));

            }

           

            System.out.println(credentials.hashCode());

           

           

      }

}

Output:

[a160091, a160093, a160097, a160092]
[a160091=sridhariyer, a160093=sridhariyer, a160097=sridhariyer, a160092=sridhariyer]
Values: sridhariyer
Values: sridhariyer
Values: sridhariyer
Values: sridhariyer
1683106425

Comparing two files

package edu.scjp.files;

import java.io.*;

public class CompareFiles {

        public static void main(String[] args) throws IOException {

                // File names to Read & Write.

                String actualFile   = "C:\\view\\test1.txt";

                String expectedFile = "C:\\view\\test2.txt";

                String descptnFile  = "C:\\view\\test3.txt";

                try{

                // Create FileReader & Writer Objects.

                FileReader actualFileReader  = new FileReader(actualFile);

                FileReader expctdFileReader  = new FileReader(expectedFile);

                FileWriter resultDesc = new FileWriter(descptnFile);

              

                // Create Buffered Object.

                BufferedReader actlFileBufRdr = new BufferedReader(actualFileReader);

                BufferedReader expcFileBufRdr = new BufferedReader(expctdFileReader);

                BufferedWriter resultFileBufWrtr = new BufferedWriter(resultDesc);

              

                // Get the file contents into String Variables.

                String actlFileContent = actlFileBufRdr.readLine();

                String expctdFileContent = expcFileBufRdr.readLine();

              

                // Compare the Contents of the files.

                String startOfComparision = "---------START----------";

                resultFileBufWrtr.write(startOfComparision);

                resultFileBufWrtr.newLine();

                System.out.println(startOfComparision);

              

                boolean isDifferent = false;

                int lineNumber = 1;

              

                if (actlFileContent != null || expctdFileContent != null) {

                      

                        // Check whether Actual file contains data or not

                        while((actlFileContent!=null)  ){

                              

                                // Check whether Expected file contains data or not

                                if (((expctdFileContent )!=null)) {

                                      

                                        // Check whether both the files have same data in the lines

                                        if (!actlFileContent.equals(expctdFileContent)) {

                                                resultFileBufWrtr.write("Difference in Line "+lineNumber+" :- Actual File contains :"+actlFileContent+", Expected File Contains : "+expctdFileContent);

                                                resultFileBufWrtr.newLine();

                                                System.out.println("Difference in Line "+lineNumber+" :- Actual File contains :"+actlFileContent+", Expected File Contains : "+expctdFileContent);

                                                isDifferent = true;

                                        }

                                        lineNumber = lineNumber+1;

                                        expctdFileContent= expcFileBufRdr.readLine();

                                }

                                else{

                                        resultFileBufWrtr.write("Difference in Line "+lineNumber+" :- Actual File contains :"+actlFileContent+", Expected File Contains - "+expctdFileContent);

                                        resultFileBufWrtr.newLine();

                                        System.out.println("Difference in Line "+lineNumber+" :- Actual File contains :"+actlFileContent+", Expected File Contains - "+expctdFileContent);

                                        isDifferent = true;

                                        lineNumber = lineNumber+1;

                                }

                                actlFileContent=actlFileBufRdr.readLine();

                        }

                      

                        // Check for the condition : if Actual File has Data & Expected File doesn't contain data.

                        while ((expctdFileContent!=null)&&(actlFileContent==null)) {

                                resultFileBufWrtr.write("Difference in Line "+lineNumber+" :- Actual File contains :"+actlFileContent+", Expected File Contains - "+expctdFileContent);

                                resultFileBufWrtr.newLine();

                                System.out.println("Difference in Line "+lineNumber+" :- Actual File contains :"+actlFileContent+", Expected File Contains - "+expctdFileContent);

                                isDifferent = true;

                                lineNumber = lineNumber+1;

                                expctdFileContent= expcFileBufRdr.readLine();

                        }

                }

                else{

                        // Mention that both the files don't have Data.

                        resultFileBufWrtr.write("Difference in Line "+lineNumber+" :- Actual File contains :"+actlFileContent+", Expected File Contains - "+expctdFileContent);

                        resultFileBufWrtr.newLine();

                        System.out.println("Difference in Line "+lineNumber+" :- Actual File contains :"+actlFileContent+", Expected File Contains - "+expctdFileContent);

                        isDifferent = true;

                }

              

                // Check is there any difference or not.

                String endOfComparision = "-----------END----------";

                if (isDifferent) {

                        resultFileBufWrtr.append(endOfComparision);

                        System.out.println(endOfComparision);

                }

                else{

                        resultFileBufWrtr.append("No difference Found");

                        resultFileBufWrtr.newLine();

                        resultFileBufWrtr.append(endOfComparision);

                      

                        System.out.println("No difference Found");

                        System.out.println(endOfComparision);

                }

              

                //Close the streams.

                actualFileReader.close();

                expctdFileReader.close();

                resultFileBufWrtr.close();

                actlFileBufRdr.close();

                expcFileBufRdr.close();

          }

          catch( FileNotFoundException e )

        {

                        e.printStackTrace();

        }             

        }

}