Java Matrices Pro

Java program to add two matrices

import java.util.Scanner;

class AddTwoMatrix

{

public static void main(String args[])

          {

      int m, n, c, d;

      Scanner in = new Scanner(System.in);

                System.out.println("Enter the number of rows and columns of matrix");

      m = in.nextInt();

      n  = in.nextInt();

      int first[][] = new int[m][n];

      int second[][] = new int[m][n];

      int sum[][] = new int[m][n];

      System.out.println("Enter the elements of first matrix");

         for (  c = 0 ; c < m ; c++ )

         for ( d = 0 ; d < n ; d++ )

            first[c][d] = in.nextInt();

      System.out.println("Enter the elements of second matrix");

         for ( c = 0 ; c < m ; c++ )

         for ( d = 0 ; d < n ; d++ )

            second[c][d] = in.nextInt();

         for ( c = 0 ; c < m ; c++ )

         for ( d = 0 ; d < n ; d++ )

             sum[c][d] = first[c][d] + second[c][d];   

      System.out.println("Sum of entered matrices:-");

         for ( c = 0 ; c < m ; c++ )

      {

         for ( d = 0 ; d < n ; d++ )

            System.out.print(sum[c][d]+"\t");

            System.out.println();

      }

   }

}

Java program to reverse number

import java.util.Scanner;

class ReverseNumber

{

   public static void main(String args[])

   {

      int n, reverse = 0;

      System.out.println("Enter the number to reverse");

      Scanner in = new Scanner(System.in);

      n = in.nextInt();

      while( n != 0 )

      {

          reverse = reverse * 10;

          reverse = reverse + n%10;

          n = n/10;

      }

      System.out.println("Reverse of entered number is "+reverse);

   }

}

Java program to get ip address

import java.net.InetAddress;

class IPAddress

{

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

{

      System.out.println(InetAddress.getLocalHost());

   }

}

Java program to perform garbage collection

import java.util.*;

class GarbageCollection

{

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

{

      Runtime rs =  Runtime.getRuntime();

      System.out.println("Free memory in JVM before Garbage Collection = "+rs.freeMemory());

      rs.gc();

      System.out.println("Free memory in JVM after Garbage Collection = "+rs.freeMemory());

   }

}

Java program to generate random numbers

import java.util.*;

class RandomNumbers 

{

 public static void main(String[] args) 

{

    int c;

    Random t = new Random();

     for (c = 1; c <= 10; c++) 

    {

      System.out.println(t.nextInt(100));

    }

  }

}

Java program to display date and time, print date and time using java program

import java.util.*;

class GetCurrentDateAndTime

{

 public static void main(String args[])

 {

      int day, month, year;

      int second, minute, hour;

      GregorianCalendar date = new GregorianCalendar();

      day = date.get(Calendar.Day_of_month);

      month = date.get(Calendar.Month);

      year = date.get(Calendar.Year);

      second = date.get(Calendar.Second);

      minute = date.get(Calendar.Minute);

      hour = date.get(Calendar.Hour);

      System.out.println("Current date is  "+day+"/"+(month+1)+"/"+year);

      System.out.println("Current time is  "+hour+" : "+minute+" : "+second);

   }

} 

Java program to find all substrings of a string

import java.util.Scanner;

class SubstringsOfAString

{

public static void main(String args[])

{

      String string, sub;

      int i, c, length;

      Scanner in = new Scanner(System.in);

      System.out.println("Enter a string to print it's all substrings");

      string  = in.nextLine();

      length = string.length();   

      System.out.println("Substrings of \""+string+"\" are :-");

      for( c = 0 ; c < length ; c++ )

      {

         for( i = 1 ; i <= length - c ; i++ )

         {

            sub = string.substring(c, c+i);

            System.out.println(sub);

         }

      }

   }

}

Java program for binary search

import java.util.Scanner;

class BinarySearch 

{

public static void main(String args[])

{

    int c, first, last, middle, n, search, array[];

    Scanner in = new Scanner(System.in);

    System.out.println("Enter number of elements");

    n = in.nextInt(); 

    array = new int[n];

    System.out.println("Enter " + n + " integers");

      for (c = 0; c < n; c++)

      array[c] = in.nextInt();

    System.out.println("Enter value to find");

    search = in.nextInt();

    first  = 0;

    last   = n - 1;

    middle = (first + last)/2;

    while( first <= last )

    {

      if ( array[middle] < search )

        first = middle + 1;    

      else if ( array[middle] == search ) 

      {

        System.out.println(search + " found at location " + (middle + 1) + ".");

        break;

      }

      else

         last = middle - 1;

      middle = (first + last)/2;

   }

   if ( first > last )

      System.out.println(search + " is not present in the list.\n");

  }

}

Java program for linear search

import java.util.Scanner;

class LinearSearch 

{

public static void main(String args[])

{

    int c, n, search, array[];

    Scanner in = new Scanner(System.in);

    System.out.println("Enter number of elements");

    n = in.nextInt(); 

    array = new int[n];

    System.out.println("Enter " + n + " integers");

      for (c = 0; c < n; c++)

      array[c] = in.nextInt();

    System.out.println("Enter value to find");

    search = in.nextInt();

    for (c = 0; c < n; c++)

    {

      if (array[c] == search)     /* Searching element is present */

      {

         System.out.println(search + " is present at location " + (c + 1) + ".");

          break;

      }

   }

   if (c == n)

      System.out.println(search + " is not present in array.");

  }

}