First Non Repeating charater in ther String
package com.example.demo.non_RepeatingChar;
public static void main(String[] args) {
String str = "Particular item P c u";
boolean flag = true;
for(char c : str.toCharArray() ) {
if(str.indexOf(c) == str.lastIndexOf(c)) {
System.out.println("First non repeating character : " + c );
flag = false;
break;
}
}
if(flag) {
System.out.println("Threr is no non repeating character in the string.");
}
}
}
Reversing a String
public class StringReverse {
public static void main(String[] args) {
String str = "Hello World How are you ?";
char[] chr = str.toCharArray();
for(int i=chr.length-1; i>=0; i--) {
System.out.print(chr[i]);
}
}
}
Vowel character in string
public class FindVowel {
public static boolean finVowelInString(String str) {
return str.toLowerCase().matches(".*[aeiou].*");
}
public static void main(String[] args) {
System.out.println(finVowelInString("Hello"));
System.out.println(finVowelInString("TV"));
}
}
public class ReverseStringWithList {
public static void main(String[] args) {
String str = "Hello World";
char[] arrayChar = str.toCharArray();
List<Character> listOfCharacter = new ArrayList<Character>();
for (char c : arrayChar) {
listOfCharacter.add(c);
}
Collections.reverse(listOfCharacter);
ListIterator li = listOfCharacter.listIterator();
while (li.hasNext()) {
System.out.print(li.next());
}
// System.out.println(listOfCharacter.toString());
}
}
package com.example.demo.LeetCode;
import java.util.HashSet;
import java.util.Set;
public class FindDupateInArray {
public static void main(String[] args) {
int[] arr = new int[] {2,3,4,5,2,3,4,4,4,2,4};
Set<Integer> set = new HashSet<Integer>();
for(int i=0;i<arr.length;i++) {
for(int j=i+1;j<arr.length;j++) {
if(arr[i]==arr[j]) {
set.add(arr[i]);
}
}
}
System.out.println(set);
}
}
package com.example.demo.LeetCode;
import java.util.HashSet;
import java.util.Set;
public class FindDupateInArray {
public static void main(String[] args) {
int[] arr = new int[] { 2, 3, 4, 5, 2, 3, 4, 4, 4, 2, 4, 90, 90, 55, 55, 5, 89, 78, 56 };
Set<Integer> set = new HashSet<Integer>();
for (int i = 0; i < arr.length; i++) {
for (int j = i + 1; j < arr.length; j++) {
if (arr[i] == arr[j]) {
set.add(arr[i]);
}
}
}
System.out.println("Duplicate Elements are : "+set);
Set<Integer> setRemoveDuplicate = new HashSet<Integer>();
for (int i = 0; i < arr.length; i++) {
for (int j = 0 ; j < arr.length; j++) {
if (arr[i] != arr[j]) {
setRemoveDuplicate.add(arr[i]);
}
}
}
System.out.println("After Removing DuplicateElements : "+setRemoveDuplicate);
}
}
package com.Fabonacci;
public class FabonacciTest {
public static void main(String[] args) {
int n1=0, n2=1, n3, i , count=10;
System.out.print(n1+" "+n2);
for(i=2; i<count;i++){
n3 = n2+n1;
System.out.print(" "+n3);
n1 = n2;
n2 = n3;
}
}
}
OUTPUT: 0 1 1 2 3 5 8 13 21 34
package com.example.demo.java_8.Second_highest_num_Array;
import java.util.SortedSet;
import java.util.TreeSet;
public class SecondHighestNumberInArray {
public static void main(String[] args) {
int[] array = new int[] { 23, 56, 89, 34, 22, 23, 56, 99, 101, 101, 101 };
SortedSet<Integer> set = new TreeSet<Integer>();
for (int element : array) {
set.add(element);
}
System.out.println(set);
set.remove(set.last());
System.out.println(set.last());
}
}
package com.example.demo.java_8.Second_highest_num_Array;
import java.util.Arrays;
public class SeconLargestNumInArray_2 {
public static void main(String[] args) {
int[] array = new int[] { 24, 68, 8, 52, 22, 47, 9, 75, 3, 24, 22,99 };
int largestNum = 0;
int secondLargestNum = 0;
for(int i=0;i<array.length;i++) {
if(array[i]>largestNum) {
secondLargestNum = largestNum;
largestNum = array[i];
}else if(array[i]>secondLargestNum) {
secondLargestNum = array[i];
}
}
System.out.println(Arrays.toString(array));
System.out.println("Second Largest number : "+ secondLargestNum );
}
}
class Rectangle {
int length;
int breadth;
public Rectangle(int length, int breadth) {
this.length = length;
this.breadth = breadth;
}
public Rectangle(Rectangle obj) {
length = obj.length;
breadth = obj.breadth ;
}
public int area() {
return length * breadth;
}
}
public class CopyConstructorTest {
public static void main(String[] args) {
Rectangle CopyfirstRectangel = new Rectangle(firstRectangel);
System.out.println("Area of Rectangle : "+firstRectangel.area());
System.out.println("Copy constructor " + CopyfirstRectangel.area());
}
}
OUTPUT:-
Copy constructor 200
package com.DuplicateArray;
public class DuplicationTest {
public static void main(String[] args) {
int arr[] = {12,15,65,12,17,15,65,98,78,78};
int len = arr.length;
for(int k=0; k<len;k++){
System.out.print(arr[k]+" ");
}
for(int i =0; i<len-1;i++){
for(int j=i+1; j<len;j++){
if(arr[i] == arr[j]){
arr[j] = arr[len-1];
len--;
}
}
}
System.out.println();
for(int k=0; k<len;k++){
System.out.print(arr[k]+" ");
}
}
}
OUTPUT:-
12 15 65 12 17 15 65 98 78 78
12 15 65 78 17 98
Removal of duplicate element from Array String form.
package com.DuplicateArray;
import java.util.Arrays;
public class StringDuplicationRemove {
public static void main(String[] args) {
String names[] = {"Ali","Kunal","Paridhi","Paridhi","Paritosh","Ali","Sakshi","Tushar"};
int len= names.length;
//Arrays.sort(names);
for(int k=0; k<len;k++){
System.out.print(names[k]+" ");
}
for(int i =0; i<len-1; i++){
for(int j=i+1; j<len; j++){
if(names[i] == names[j]){
names[i] = names[len-1];
len--;
}
}
}
System.out.println();
for(int k=0; k<len;k++){
System.out.print(names[k]+" ");
}
System.out.println();
for(int k=0; k<names.length;k++){
System.out.print(names[k] + " ");
}
}
}
----------------------------------------------------------------------------------------------------------
Arrays.sort() in Java with examples
// A sample Java program to sort an array of integers// using Arrays.sort(). It by default sorts in// ascending orderimport java.util.Arrays;public class SortExample{ public static void main(String[] args) { // Our arr contains 8 elements int[] arr = {13, 7, 6, 45, 21, 9, 101, 102}; Arrays.sort(arr); System.out.printf("Modified arr[] : %s", Arrays.toString(arr)); }} |
Modified arr[] : [6, 7, 9, 13, 21, 45, 101, 102]
// A sample Java program to sort a subarray// using Arrays.sort().import java.util.Arrays;public class SortExample{ public static void main(String[] args) { // Our arr contains 8 elements int[] arr = {13, 7, 6, 45, 21, 9, 2, 100}; // Sort subarray from index 1 to 4, i.e., // only sort subarray {7, 6, 45, 21} and // keep other elements as it is. Arrays.sort(arr, 1, 5); System.out.printf("Modified arr[] : %s", Arrays.toString(arr)); }} |
Modified arr[] : [13, 6, 7, 21, 45, 9, 2, 100]
// A sample Java program to sort a subarray// in descending order using Arrays.sort().import java.util.Arrays;import java.util.Collections;public class SortExample{ public static void main(String[] args) { // Note that we have Integer here instead of // int[] as Collections.reverseOrder doesn't // work for primitive types. Integer[] arr = {13, 7, 6, 45, 21, 9, 2, 100}; // Sorts arr[] in descending order Arrays.sort(arr, Collections.reverseOrder()); System.out.printf("Modified arr[] : %s", Arrays.toString(arr)); }} |
Modified arr[] : [100, 45, 21, 13, 9, 7, 6, 2]
// A sample Java program to sort an array of strings// in ascending and descending orders using Arrays.sort().import java.util.Arrays;import java.util.Collections;public class SortExample{ public static void main(String[] args) { String arr[] = {"practice.geeksforgeeks.org", "quiz.geeksforgeeks.org", "code.geeksforgeeks.org" }; // Sorts arr[] in ascending order Arrays.sort(arr); System.out.printf("Modified arr[] : \n%s\n\n", Arrays.toString(arr)); // Sorts arr[] in descending order Arrays.sort(arr, Collections.reverseOrder()); System.out.printf("Modified arr[] : \n%s\n\n", Arrays.toString(arr)); }} |
Modified arr[] : Modified arr[] : [quiz.geeksforgeeks.org, practice.geeksforgeeks.org, code.geeksforgeeks.org]
Find The First Non Repeated Character In A String : Technical Interview Question
If the word "teeter" is input then it should print 'r' as output .
Now , we should understand the pseudo algorithm or logic to achieve this task , code is given in the end of this post .
import java.util.HashMap;
import java.util.Scanner;
public class FirstNonRepeated {
public static void main(String[] args)
{
// TODO Auto-generated method stub
System.out.println(" Please enter the input string :" );
Scanner in = new Scanner (System.in);
String s=in.nextLine();
char c=firstNonRepeatedCharacter(s);
System.out.println("The first non repeated character is : " + c);
}
public static Character firstNonRepeatedCharacter(String str)
{
HashMap<Character,Integer> characterhashtable= new HashMap<Character ,Integer>();
int i,length ;
Character c ;
length= str.length(); // Scan string and build hash table
for (i=0;i < length;i++)
{
c=str.charAt(i);
if(characterhashtable.containsKey(c))
{
// increment count corresponding to c
characterhashtable.put( c , characterhashtable.get(c) +1 );
}
else
{
characterhashtable.put( c , 1 ) ;
}
}
// Search characterhashtable in in order of string str
for (i =0 ; i < length ; i++ )
{
c= str.charAt(i);
if( characterhashtable.get(c) == 1 )
return c;
}
return null ;
}
} Count Number
Of Words In The String With Example :
Java Program Code
public class StringDemo { static int i,c=0,res; static int wordcount(String s) { char ch[]= new char[s.length()]; //in string especially we have to mention the () after length for(i=0;i<s.length();i++) { ch[i]= s.charAt(i); if( ((i>0)&&(ch[i]!=' ')&&(ch[i-1]==' ')) || ((ch[0]!=' ')&&(i==0)) ) c++; } return c; } public static void main (String args[]) { res=StringDemo.wordcount(" manchester united is also known as red devil "); //string is always passed in double quotes System.out.println("The number of words in the String are : "+res); } }2.public static int countWordsUsingSplit(String input) { if (input == null || input.isEmpty()) { return 0; } String[] words = input.split("\\s+"); return words.length; }
Read more:3.public static int countWordsUsingStringTokenizer(String sentence) {if (sentence == null || sentence.isEmpty()) { return 0; } StringTokenizer tokens = new StringTokenizer(sentence); return tokens.countTokens(); }4.public static int count(String word) { if (word == null || word.isEmpty()){ return 0; }int wordCount = 0;boolean isWord = false;int endOfLine = word.length() - 1;char[] characters = word.toCharArray();for (int i = 0; i < characters.length; i++){ // if the char is a letter, word = true. if (Character.isLetter(characters[i]) && i != endOfLine) { isWord = true; // if char isn't a letter and there have been letters before, // counter goes up. } else if (!Character.isLetter(characters[i]) && isWord) { wordCount++; isWord = false; // last word of String; if it doesn't end with a non letter, it // wouldn't count without this. } else if (Character.isLetter(characters[i]) && i == endOfLine) { wordCount++; } } return wordCount; }
