Java program codes: 01/07/17

Saturday, 7 January 2017

Swap Numbers Without Using Third Variable Java Example

public class SwapElementsWithoutThirdVariableExample {
public static void main(String[] args) {
int num1 = 10;
int num2 = 20;
System.out.println("Before Swapping");
System.out.println("Value of num1 is :" + num1);
System.out.println("Value of num2 is :" +num2);
//add both the numbers and assign it to first
num1 = num1 + num2;
num2 = num1 - num2;
num1 = num1 - num2;
System.out.println("Before Swapping");
System.out.println("Value of num1 is :" + num1);
System.out.println("Value of num2 is :" +num2);
}
}

Find Largest and Smallest Number in an Array Example

public class FindLargestSmallestNumber {
public static void main(String[] args) {
//array of 10 numbers
int numbers[] = new int[]{32,43,53,54,32,65,63,98,43,23};
//assign first element of an array to largest and smallest
int smallest = numbers[0];
int largetst = numbers[0];
for(int i=1; i< numbers.length; i++)
{
if(numbers[i] > largetst)
largetst = numbers[i];
else if (numbers[i] < smallest)
smallest = numbers[i];
}
System.out.println("Largest Number is : " + largetst);
System.out.println("Smallest Number is : " + smallest);
}
}

reverse of a given string

import java.util.*;
 
class ReverseString
{
   public static void main(String args[])
   {
      String original, reverse = "";
      Scanner in = new Scanner(System.in);
 
      System.out.println("Enter a string to reverse");
      original = in.nextLine();
 
      int length = original.length();
 
      for ( int i = length - 1 ; i >= 0 ; i-- )
         reverse = reverse + original.charAt(i);
 
      System.out.println("Reverse of entered string is: "+reverse);
   }
}

string palindrome

import java.util.*;
 
class Palindrome
{
   public static void main(String args[])
   {
      String original, reverse = "";
      Scanner in = new Scanner(System.in);
 
      System.out.println("Enter a string to check if it is a palindrome");
      original = in.nextLine();
 
      int length = original.length();
 
      for ( int i = length - 1; i >= 0; i-- )
         reverse = reverse + original.charAt(i);
 
      if (original.equals(reverse))
         System.out.println("Entered string is a palindrome.");
      else
         System.out.println("Entered string is not a palindrome.");
 
   }
}

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++;
      }         
   }
}

armstrong number

This java program checks if a number is Armstrong or not. Armstrong 
number is a number which is equal to sum of digits raise to the power 
total number of digits in the number. Some Armstrong numbers are: 0, 1, 
4, 5,  9, 153, 371, 407, 8208 etc.

import java.util.Scanner;
 
class ArmstrongNumber
{
   public static void main(String args[])
   {
      int n, sum = 0, temp, remainder, digits = 0;
 
      Scanner in = new Scanner(System.in);
      System.out.println("Input a number to check if it is an Armstrong number");      
      n = in.nextInt();
 
      temp = n;
 
      // Count number of digits
 
      while (temp != 0) {
         digits++;
         temp = temp/10;
      }
 
      temp = n;
 
      while (temp != 0) {
         remainder = temp%10;
         sum = sum + power(remainder, digits);
         temp = temp/10;
      }
 
      if (n == sum)
         System.out.println(n + " is an Armstrong number.");
      else
         System.out.println(n + " is not an Armstrong number.");         
   }
 
   static int power(int n, int r) {
      int c, p = 1;
 
      for (c = 1; c <= r; c++) 
         p = p*n;
 
      return p;   
   }
}

factorial

import java.util.Scanner;
 
class Factorial
{
   public static void main(String args[])
   {
      int n, c, fact = 1;
 
      System.out.println("Enter an integer to calculate it's factorial");
      Scanner in = new Scanner(System.in);
 
      n = in.nextInt();
 
      if ( n < 0 )
         System.out.println("Number should be non-negative.");
      else
      {
         for ( c = 1 ; c <= n ; c++ )
            fact = fact*c;
 
         System.out.println("Factorial of "+n+" is = "+fact);
      }
   }
}

Fahrenheit to Celsius

import java.util.*;
 
class FahrenheitToCelsius {
  public static void main(String[] args) {
    float temperatue;
    Scanner in = new Scanner(System.in);      
 
    System.out.println("Enter temperatue in Fahrenheit");
    temperatue = in.nextInt();
 
    temperatue = ((temperatue - 32)*5)/9;
 
    System.out.println("Temperatue in Celsius = " + temperatue);
  }
}

Interface in Java

interface Info {
  static final String language = "Java";  
  public void display();
}
 
class Simple implements Info {
  public static void main(String []args) {
    Simple obj = new Simple();
    obj.display();
  } 
 
  // Defining method declared in interface
 
  public void display() {
    System.out.println(language + " is awesome");
  } 
}

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)  /* Searching element is absent */
      System.out.println(search + " is not present in array.");
  }
}

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");
  }
}

addition of 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];  //replace '+' with '-' to subtract matrices
 
      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 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");
      }
   }
}

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");
         }
      }
   }
}

bubble sort

import java.util.Scanner;
 
class BubbleSort {
  public static void main(String []args) {
    int n, c, d, swap;
    Scanner in = new Scanner(System.in);
 
    System.out.println("Input number of integers to sort");
    n = in.nextInt();
 
    int array[] = new int[n];
 
    System.out.println("Enter " + n + " integers");
 
    for (c = 0; c < n; c++) 
      array[c] = in.nextInt();
 
    for (c = 0; c < ( n - 1 ); c++) {
      for (d = 0; d < n - c - 1; d++) {
        if (array[d] > array[d+1]) /* For descending order use < */
        {
          swap       = array[d];
          array[d]   = array[d+1];
          array[d+1] = swap;
        }
      }
    }
 
    System.out.println("Sorted list of numbers");
 
    for (c = 0; c < n; c++) 
      System.out.println(array[c]);
  }
}

Java exception handling

class Division {
  public static void main(String[] args) {
 
  int a, b, result;
 
  Scanner input = new Scanner(System.in);
  System.out.println("Input two integers");
 
  a = input.nextInt();
  b = input.nextInt();
 
  // try block
 
  try {
    result  = a / b;
    System.out.println("Result = " + result);
  }
 
  // catch block
 
  catch (ArithmeticException e) {
    System.out.println("Exception caught: Division by zero.");
  }
  }
}

Floyd's triangle

import java.util.Scanner;
 
class FloydTriangle
{
   public static void main(String args[])
   {
      int n, num = 1, c, d;
      Scanner in = new Scanner(System.in);
 
      System.out.println("Enter the number of rows of floyd's triangle you want");
      n = in.nextInt();
 
      System.out.println("Floyd's triangle :-");
 
      for ( c = 1 ; c <= n ; c++ )
      {
         for ( d = 1 ; d <= c ; d++ )
         {
            System.out.print(num+" ");
            num++;
         }
 
         System.out.println();
      }
   }
}

String comparisons

import java.util.Scanner;
 
class CompareStrings
{
   public static void main(String args[])
   {
      String s1, s2;
      Scanner in = new Scanner(System.in);
 
      System.out.println("Enter the first string");
      s1 = in.nextLine();
 
      System.out.println("Enter the second string");
      s2 = in.nextLine();
 
      if ( s1.compareTo(s2) > 0 )
         System.out.println("First string is greater than second.");
      else if ( s1.compareTo(s2) < 0 )
         System.out.println("First string is smaller than second.");
      else   
         System.out.println("Both strings are equal.");
   }
}