Java programs

no.of occurance of a letter:

public class countexample {

public static void main(String args[]){  

String input="meeraja";

int charCount = 0; //resetting character count

    for(char ch: input.toCharArray()){

        if(ch == 'a'){

            charCount++;

        }

    }     

    System.out.println("count of character 'a' on String: " + charCount);

}

}

Fibonacci:

public class fibonacc {

public static void main(String[]args){

int num=8;

int current = 1;

int last = 0;

int lastlast;

for(int i=0;i<num;i++){

lastlast=last;

last=current;

current= last + lastlast;

System.out.println(current);

}}}

Bubble sort:

public class bubblesort1 {

static int num[]={2,5,45,23};

public static void main(String[] args) {

System.out.println("before sort");

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

System.out.println(num[i]);

}

int temp;

for(int i=num.length-1;i>0;i--)

{

for(int j=0;j<i;j++){

if(num[j]>num[j +1]){

temp=num[j];

num[j]= num[j+1];

num[j+1]=temp;

}}}

for(int k=0;k<num.length;k++)  

System.out.println(num[k]);

}

Sort integer array:

public class sort_int_example {

public static void main(String[]args){

//Sorting integers

  

  int a[] = {10,5,6,3};

  a = sort(a);

  for(int i:a)

  System.out.println(i);

}

  public static int[] sort(int[] a)

  {

  int n = a.length;

  int temp;

  

  for(int i=0;i<n-1;++i)

  {

  for(int j=0;j<n-i-1;j++)

  {

  if(a[j]>a[j+1])

  {

  temp = a[j];

  a[j] = a[j+1];

  a[j+1] = temp;

  }

  }

  }

  return a;

  }

}

sort a string:

public class sort_exam {

public static void main(String[] args){

   String wordSt="watch";

   char[] word=wordSt.toCharArray();

int n=wordSt.length();

   for(int i=0;i<(n-1);i++){

    //for(int j=0;j<n-i-1;j++){

      for(int j=i+1;j>0;j--){

           if(word[j]<word[j-1]){

               char temp=word[j-1];

               word[j-1]=word[j];

               word[j]=temp;

           }

       }

   }

   wordSt=String.valueOf(word);

   System.out.println(wordSt);

}

}

**********************************************************

public class string_sort {

public static void main(String args[]){

sort("meeraja");

}

public static String sort(String str)

  {

  StringBuffer result = null;

  

  if(str!=null && str.length()>0)

  {

  

  char[] chars = new char[str.length()];

  result = new StringBuffer(chars.length);

  

  for(int i=0;i<chars.length;++i)

  chars[i] = str.charAt(i);

  

  //character array is ready to sort

  int n = chars.length;

  char temp;

  for(int i=0;i<n-1;++i)

  {

  for(int j=0;j<n-i-1;j++)

  {

  if(chars[j]>chars[j+1])

  {

  temp = chars[j];

  chars[j] = chars[j+1];

  chars[j+1] = temp;

  }

  }

  }

  

  for(char c:chars)

  {

  System.out.print(c);

  result.append(c);

  }

  return result.toString();  

  }

  return str;

  

  }

}

String array sorting:

public class Str_Examples {

public static void main(String[]args){

//Sorting strings

  String names[] = {"Sanjay","Sriram","Meeraja","Ramana"};

  names = sort(names);

  for(String name1:names)

  System.out.println(name1); }

public static String[] sort(String[] a)

  {

  int n = a.length;

  System.out.println(n);

  String temp;

  

  for(int i=0;i<n-1;++i)

  {

  for(int j=0;j<n-i-1;j++)

  {

  if(a[j].compareTo(a[j+1])>0)

  {

  temp = a[j];

  a[j] = a[j+1];

  a[j+1] = temp;

  }

  }

FInd largest number:

1. 
   
   1. Find Largest and Smallest Number
   2.  /*
   3.   Find Largest and Smallest Number in an Array Example
   4.   This Java Example shows how to find largest and smallest number in an
   5.   array.
   6. */
   7. public class FindLargestSmallestNumber {
   9.         public static void main(String[] args) {
   10.                
   11.                 //array of 10 numbers
   12.                 int numbers[] = new int[]{32,43,53,54,32,65,63,98,43,23};
   13.                
   14.                 //assign first element of an array to largest and smallest
   15.                 int smallest = numbers[0];
   16.                 int largetst = numbers[0];
   17.                
   18.                 for(int i=1; i< numbers.length; i++)
   19.                 {
   20.                         if(numbers[i] > largetst)
   21.                                 largetst = numbers[i];
   22.                         else if (numbers[i] < smallest)
   23.                                 smallest = numbers[i];
   24.                        
   25.                 }
   26.                
   27.                 System.out.println("Largest Number is : " + largetst);
   28.                 System.out.println("Smallest Number is : " + smallest);
   29.         }
   30. }
   32. /*
   33. Output of this program would be
   34. Largest Number is : 98
   35. Smallest Number is : 23
   36. */

FindEvenOrOddNumber

1. /*
2.   Even Odd Number Example
3.   This Java Even Odd Number Example shows how to check if the given
4.   number is even or odd.
5. */
7. public class FindEvenOrOddNumber {
9.         public static void main(String[] args) {
10.                
11.                 //create an array of 10 numbers
12.                 int[] numbers = new int[]{1,2,3,4,5,6,7,8,9,10};
13.                
14.                 for(int i=0; i < numbers.length; i++){
15.                        
16.                         /*
17.                          * use modulus operator to check if the number is even or odd. 
18.                          * If we divide any number by 2 and reminder is 0 then the number is
19.                          * even, otherwise it is odd.
20.                          */
21.                          
22.                          if(numbers[i]%2 == 0)
23.                                 System.out.println(numbers[i] + " is even number.");
24.                          else
25.                                 System.out.println(numbers[i] + " is odd number.");
26.                                
27.                 }
28.                
29.         }
30. }
32. /*
33. Output of the program would be
34. 1 is odd number.
35. 2 is even number.
36. 3 is odd number.
37. 4 is even number.
38. 5 is odd number.
39. 6 is even number.
40. 7 is odd number.
41. 8 is even number.
42. 9 is odd number.
43. 10 is even number.
44. */

remove duplicates from an array:


import java.util.HashSet;

public class test {
static int[] array = {4, 3, 3, 4, 5, 2, 4};
static HashSet l = new HashSet();
public static void main(String ar[])
{       
    for(int i=0;i<array.length;i++)
    {         
      l.add(array[i]);

    }
    System.out.println(l);
}}


Reverse a numbere:

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 – Reverse String without using Reverse function

package JavaPrograms;
import java.util.*;
public 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);
  }
}




Java – Remove Duplicate Number from Array


package JavaPrograms;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class RemoveduplicateArray {


//  Remove duplicate entries from an array of long integers

    public static void main(String[] args)
    {
        //
        // A long integer array with some duplicated values
        //
        long [] longArray = { 11,0, 11, 22, 44, 55, 66, 77, 88, 0, 99, 77, 66, 42, 55, 66, 99, 11};

        System.out.println("Original array size = " + longArray.length);
        System.out.println("Original array            : " +
                Arrays.toString(longArray));

        //
        // Want to let Java convert the array to a Set, since
        // the Set object won't have duplicate entries.
        //
        // But first...
        //
        // Since the Set constructor needs a List (not an array),
        // "convert" the array to a List.
        //
        List<Long> longList = new ArrayList<Long>();
        for (int i = 0; i < longArray.length; i++)
        {
            longList.add(longArray[i]);
        }

        // Now, instantiate a Set with its constructor that has a List argument
        Set <Long> longSet = new HashSet<Long>(longList);

        //
        // Create an array of Long objects and use Set.toArray()
        // to "convert" the Set to the array.
        Long[] resultNoDups = new Long[longSet.size()];
        longSet.toArray(resultNoDups);

        // Finally, if we want an array of long ints rather
        // than an array of Long objects, create the array
        // and copy the values
        long [] finalArray = new long[resultNoDups.length];
        for (int i = 0; i < resultNoDups.length; i++) {
            finalArray[i] = resultNoDups[i];
        }

        // Taa-daa
        System.out.println("After removing duplicates : " +
                Arrays.toString(finalArray));

        System.out.println("Result array size = " + finalArray.length);
        System.out.println();
    }
}


Program to Find Prime Number

package JavaPrograms;
import java.util.*;

public class PrimeNumber {
//Note: Scanner class work with JDK1.5 or above

public static void main(String args[])
{
int n, i, res;
boolean flag=true;

System.out.println("Please Enter a No.");
Scanner scan= new Scanner(System.in);
n=scan.nextInt();
for(i=2;i<=n/2;i++)
{
res=n%i;
if(res==0)
{
flag=false;
break;
}
}
if(flag)
System.out.println(n + " is Prime Number");
else
System.out.println(n + " is not Prime Number");
}
}



Program Palindrome Series

package JavaPrograms;
import java.util.*;
public 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.");

  }
}



Integer array sorting:

package JavaExamplea;

public class sort_int_example {

public static void main(String[]args){

//Sorting integers

  int a[] = {10,5,6,3};
  a = sort(a);
  for(int i:a)
  System.out.println(i);

}

  public static int[] sort(int[] a)
  {
  int n = a.length;
  int temp;

  for(int i=0;i<n-1;++i)
  {
  for(int j=0;j<n-i-1;j++)
  {
  if(a[j]>a[j+1])
  {
  temp = a[j];
  a[j] = a[j+1];
  a[j+1] = temp;
  }
  }
  }
  return a;
  }

}

Program to find Fibonacci series of a given number

package JavaPrograms;

public class fabonacciSeries {

/*Write a program to find Fibonacci series of a given no.
 Example :
 Input - 8
 Output - 1 1 2 3 5 8 13 21
*/

public static void main(String args[])
{
int num = 6; //taking no. as command line argument.
System.out.println("*****Fibonacci Series*****");
int f1=0, f2=0, f3=1, f4=0, temp=0;
for(int i=1;i<=num;i++){
System.out.print(" "+f3+" ");
temp =f1+f2-1;
f1 = f2;
f2 = f3;
f3 = f1 + f2;

f4 = f3 + temp;
}
System.out.print(" \n sum of Fabonacci series numbers "+f4+" ");
}
}


Compare Two Array Program

package JavaPrograms;

public class CompareArray {

public static void compareArrays(int[] array1, int[] array2) {
boolean b = true;
if (array1 != null && array2 != null){
if (array1.length != array2.length)
b = false;
else
for (int i = 0; i < array2.length; i++) {
if (array2[i] != array1[i]) {
b = false;
}
}
}else{
b = false;
}
System.out.println(b);
}
}


BubbleSort Program

package JavaPrograms;

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]);
}
}

Program Array to Vector

package JavaPrograms;
import java.util.*;
public class ArraytoVector {

public static void main(String[] args) {
// declare and initialize array of object of given class.
Object[] arrObject = {"Manish", new Date(), "Rajesh"};
//create list for this object array.
List list = Arrays.asList(arrObject);
// create vector for given list.
Vector vector = new Vector(list);
// access the elements of the vector.
Enumeration enume = vector.elements();
while (enume.hasMoreElements()) {
System.out.println(enume.nextElement().toString());
}
}
}

Reverse String Array 

1. /*
2.         Java Reverse String Array Example
3.         This Java Reverse String Array example shows how to find sort an array of
4.         String in Java using Arrays and Collections classes.
5.  */
7. import java.util.Collections;
8. import java.util.List;
9. import java.util.Arrays;
11. public class ReverseStringArrayExample {
12.        
13.         public static void main(String args[]){
14.                
15.                 //String array
16.                 String[] strDays = new String[]{"Sunday", "Monday", "Tuesday","Wednesday"};
17.                
18.                 /*
19.                  * There are basically two methods, one is to use temporary array and
20.                  * manually loop through the elements of an Array and swap them or to use
21.                  * Arrays and Collections classes.
22.                  *
23.                  * This example uses the second approach i.e. without temp variable.
24.                  *
25.                  */
26.                
27.                 //first create a list from String array
28.                 List<String> list = Arrays.asList(strDays);
29.                
30.                 //next, reverse the list using Collections.reverse method
31.                 Collections.reverse(list);
32.                
33.                 //next, convert the list back to String array
34.                 strDays = (String[]) list.toArray();
35.                
36.                 System.out.println("String array reversed");
37.                
38.                 //print the reversed String array
39.                 for(int i=0; i < strDays.length; i++){
40.                         System.out.println(strDays[i]);
41.                 }
42.                
43.         }
45. }
47. /*
48. Output of above given Java Reverse String Array example would be
49. String array reversed
50. Wednesday
51. Tuesday
52. Monday
53. Sunday
54. */