Java Linked Hashmap Pro

Check if a particular key exists in Java Linked Hash Map

import java.util.LinkedHashMap;

public class CheckKeyOfLinkedHashMapExample

{

public static void main(String[] args)

{

LinkedHashMap lHashMap = new LinkedHashMap();

lHashMap.put("1","One");

lHashMap.put("2","Two");

lHashMap.put("3","Three");

boolean blnExists = lHashMap.containsKey("3");

System.out.println("3 exists in LinkedHashMap ? : " + blnExists);

   }

}

Print prime numbers

import java.util.*;

class PrimeNumbers

{

public static void main(String args[])

{

      int n, status = 1, num = 3;

      Scanner in = new Scanner(System.in);

      System.out.println("Enter the number of prime numbers you want");

      n = in.nextInt();

      if (n >= 1)

      {

         System.out.println("First "+n+" prime numbers are :-");

         System.out.println(2);

      }

      for ( int count = 2 ; count <=n ;  )

      {

         for ( int j = 2 ; j <= Math.sqrt(num) ; j++ )

         {

            if ( num%j == 0 )

            {

               status = 0;

               break;

            }

         }

         if ( status != 0 )

         {

            System.out.println(num);

            count++;

         }

         status = 1;

         num++;

      }        

   }

}

Java program to multiply two matrices

import java.util.Scanner;

class MatrixMultiplication

{

public static void main(String args[])

          {

      int m, n, p, q, sum = 0, c, d, k;

      Scanner in = new Scanner(System.in);

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

      m = in.nextInt();

      n = in.nextInt();

      int first[][] = 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 number of rows and columns of second matrix");

      p = in.nextInt();

      q = in.nextInt();

         if ( n != p )

         System.out.println("Matrices with entered orders can't be multiplied with each other.");

      else

      {

         int second[][] = new int[p][q];

         int multiply[][] = new int[m][q];

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

        for ( c = 0 ; c < p ; c++ )

            for ( d = 0 ; d < q ; d++ )

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

         for ( c = 0 ; c < m ; c++ )

         {

            for ( d = 0 ; d < q ; d++ )

            {   

               for ( k = 0 ; k < p ; k++ )

               {

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

               }

               multiply[c][d] = sum;

               sum = 0;

            }

         }

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

         for ( c = 0 ; c < m ; c++ )

         {

            for ( d = 0 ; d < q ; d++ )

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

            System.out.print("\n");

         }

      }

   }

}

Java program to transpose matrix

import java.util.Scanner;

class TransposeAMatrix

{

 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 matrix[][] = new int[m][n];

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

   for ( c = 0 ; c < m ; c++ )

         for ( d = 0 ; d < n ; d++ )

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

         int transpose[][] = new int[n][m];

      for ( c = 0 ; c < m ; c++ )

      {

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

            transpose[d][c] = matrix[c][d];

      }

      System.out.println("Transpose of entered matrix:-");

      for ( c = 0 ; c < n ; c++ )

      {

         for ( d = 0 ; d < m ; d++ )

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

         System.out.print("\n");

      }

   }

}