Java Program to check whether Kaprekar Number or not

public class KaprekarNumber {
public static void meth(int n) {
int temp, k, a = 0, r, rem, quo;
temp = n;
k = n * n;
while (n > 0) {
r = n % 10;
a++;
n = n / 10;
}
rem = k % ((int) Math.pow(10, a));
quo = k / ((int) Math.pow(10, a));
if ((rem + quo) == temp)
System.out.println("kaprekar number");
else
System.out.println(" not kaprekar number");
}

public static void main(String ar[]) {
meth(45);
}
}

Output:

45 is karprekar number because 45 squre = 2025 = 20+25 

like this we can check whether the given number  is karpreker number or not.

Insertion Sorting In Java

public class InsertionSort {
public static void main(String arg[]) {
int arr[] = { 25, 17, 31, 13, 2, 34, 26, 82, 22, 30 };
int i, j, k, temp;
System.out.print("Insertion sort.\n");
System.out.print("\nArray before sorting:\n");
for (i = 0; i <= 9; i++)
System.out.print(arr[i] + " ");
for (i = 1; i <= 9; i++) {
for (j = 0; j < i; j++) {
if (arr[j] > arr[i]) {
temp = arr[j];
arr[j] = arr[i];
for (k = i; k > j; k--)
arr[k] = arr[k - 1];
arr[k + 1] = temp;
}
}
}
System.out.print("\n\nArray after sorting:\n");
for (i = 0; i <= 9; i++)
System.out.print(arr[i] + " ");
}
}

OUTPUT :

Insertion sort.

Array before sorting:

25 17 31 13 2 34 26 82 22 30 

Array after sorting:

2 13 17 22 25 26 30 31 34 82 

String reverse,trim() without predefined methods in java

Reverse :

public class StringReverse {
public static void main(String[] args) {
String str = "kavuri";
char[] s = new char[str.length()];
for (int j = 0, i = (str.length() - 1); i >= 0; i--) {
s[j++] = str.charAt(i);
}
System.out.println("the given string is--" + str);
System.out.println(s);
}
}


trim() without method :

public class RemoveSpaces {

public static void main(String[] args) {
String s = "      welcome   obama      ";
String s1 = "";
for (int i = 0; i < s.length(); i++) {
if (s.charAt(i) == ' ') {
continue;
} else {
s1 += s.charAt(i);
}
}
System.out.println(s1);
}
}

Serialization Sample Code in Java

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
class Animal1 implements Serializable {
int i = 10;
Animal1() {
System.out.println("Animal");
}
}

class Dog1 extends Animal1 {
int j = 20;

Dog1() {
System.out.println("Dog");
}
}

public class SerializationSample {
public static void main(String[] args) throws Exception {
Dog1 d = new Dog1();
d.i = 30;
d.j = 40;
FileOutputStream fos = new FileOutputStream("s.txt");//it will create file in current directory
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(d);
FileInputStream fis = new FileInputStream("s.txt");
ObjectInputStream ois = new ObjectInputStream(fis);
Dog1 d1 = (Dog1) ois.readObject();
System.out.println(d1.i);
System.out.println(d1.j);
}
}

Java Program to Find where the Ascending order breaks in the existed sequence

public class CheckAscList {
/**
* @Order checking
*/
public static void main(String[] args) {
int[] intArray = { 1, 3, 5, 6, 7, 8, 11, 13, 15, 4, 17, 19, 21, 23 };
for (int i = 0; i < intArray.length - 1; i++) {
if (intArray[i] > intArray[i + 1]) {
System.out
.println("Ascending order of the list breaks at index =>> "
+ (i + 1) + " and the element is =>> "
+ intArray[i + 1]);
}
}
}
}

OUTPUT1:

Ascending order of the list breaks at index =>> 9 and the element is =>> 4

2)To find where Descending order is breaking

public class CheckDscList {

/**

* @CheckDcsList

*/

public static void main(String[] args) {

int[] intArray = { 23,21,19,18,17,15,4,12,10,8,7,5,3,2 };

for (int i = 0; i < intArray.length - 1; i++) {

if (intArray[i] < intArray[i + 1]) {

System.out

.println("Descending order of the list breaks at index =>> "

+ (i) + " and the element is =>> "

+ intArray[i]);

}

}

}

}

OUTPUT2:

Descending order of the list breaks at index =>> 6 and the element is =>> 4

Java program to count characters, numbers and white spaces in String

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class StringInspection {
public static void main(String[] args) throws Exception {
String s;
System.out.println("enter a sentence-->");
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
s = br.readLine();
int length = s.length();
int letters = 0;
int numbers = 0;
int spaces = 0;
for (int i = 0; i < length; i++) {
char ch;
ch = s.charAt(i);
if (Character.isLetter(ch)) {
letters++;
} else {
if (Character.isDigit(ch)) {
numbers++;
} else {
if (Character.isWhitespace(ch)) {
spaces++;
} else
continue;
}
}
}
System.out.println("Number of letters::" + letters);
System.out.println("Number of digits::" + numbers);
System.out.println("Number of white spaces:::" + spaces);
}
}

output::
enter a sentence--->
i am james bond 007
Number of characters: : 12  
Number of digits::  3
Number of white spaces::: 4

Bubble Sorting Java program

import java.io.BufferedReader;
import java.io.InputStreamReader;
public class BubbleSortDemo {
public static void main(String[] args)throws Exception {
BufferedReader bReader=new BufferedReader(new InputStreamReader(System.in));
System.out.println("enter how many elaments u want:");
int n=Integer.parseInt(bReader.readLine());
int arr[]=new int[n];
for(int i=0;i<n;i++){
System.out.println("Enter int value:");
arr[i]=Integer.parseInt(bReader.readLine());
}
int limit=n-1;
boolean flag=false;
int temp;
for(int i=0;i<limit;i++){
for(int j=0;j<=limit-i;j++){
if(arr[j]>arr[j+1]){
temp=arr[j];
arr[j]=arr[j+1];
arr[j+1]=temp;
flag=true;
}
}
if(flag==false) break;
else flag=false;
}
System.out.println("the sorted array::");
for(int i=0;i<n;i++)
System.out.println(arr[i]);
}
}