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How to reverse the word after getting a Capital letter at the end of the word in JAVA?

Suppose you have a String and a CAPITAL letter in that indicates ending of a word. For example, if you have wElovEcakE where E, E and K indicates end of the words wE, lovE and cakE respectively. You need to reverse each word (as you know where it ends). Don’t reverse the String as a whole. To illustrate, if we give wElovEcakE as input output should be EwEvolEkac. See wE became Ew, lovE became Evol and so on....
And the way i tried to approach with ..
import java.util.Scanner;
public class Alternative {
public static void main(String[]args) {
Scanner robo=new Scanner (System.in);
System.out.println("Enter a word ");
String word=robo.nextLine();
char[] array=word.toCharArray();
for(int i =0;i<array.length;i++){
int count =0;
for(int j=0;j<=("EMPTY");j++) // here i am trying to operate a loop where it will work up to the Capital letter.
count ++;
}
//Code incomplete
}
}
}
Above i have mentioned "EMPTY" in the condition part ... i want to operate a loop where my loop will work up to the capital letter , then i will count all the letter that i have counted up to capital letter then last step will be like i will make another loop where i will reverse all the letter where condition for the loop will <=count ;Example:lovE (counted 4 letters i will reverse four times back).
Can you guys help me to write the condition at "EMPTY" part if you think that my approach is correct ..
Can you guys help me to solve the problem in any other way ?

test if this works for you:
Scanner robo = new Scanner (System.in);
System.out.println("Enter a word ");
String word = robo.nextLine();
String textInvert = "";
int indexAnt = 0;
for (int i = 0; i < word.length(); i++) {
if (Character.isUpperCase(word.charAt(i))) {
String wordSplit = word.substring(indexAnt, i + 1);
for (int j = wordSplit.length() - 1; j >= 0; j--)
textInvert += wordSplit.charAt(j);
indexAnt = i + 1;
}
}
System.out.println(textInvert);

Here is my solution with Regex pattern
String[] in = "wElovEcakE".replaceAll("([A-z]+?[A-Z])","$1,").replaceAll(",$","").split(",");
String out = "";
for(String current: in){
StringBuilder temp = new StringBuilder();
temp.append(current);
out+=temp.reverse();
}
System.out.println(out);
Result:
EwEvolEkac

Here is a solution that makes use of the StringBuilder class to hold and reverse each found word.
Scanner robo = new Scanner (System.in);
System.out.println("Enter a word:");
String word = robo.nextLine();
robo.close();
String upperCase = word.toUpperCase(); //used to find uppercase letters
StringBuilder builder = new StringBuilder();
for (int i = 0; i < word.length(); i++) {
char nextChar = word.charAt(i);
builder.append(nextChar);
if (nextChar == upperCase.charAt(i)) {
String subWord = builder.reverse().toString();
System.out.print(subWord); //It's not clear what to do with the found words
builder = new StringBuilder();
}
}
System.out.println();
Example
Enter a word:
makEmorEpiE
EkamEromEip

You can try this solution:
String textInvert = "wElovEcakE";
String revertText = textInvert
.chars().mapToObj(c -> (char) c)
.reduce(new LinkedList<>(Arrays.asList(new StringBuilder())), (a, v) -> {
a.getLast().append(v);
if (Character.isUpperCase(v)) {
a.add(new StringBuilder());
}
return a;
}, (a1, a2) -> a1)
.stream()
.map(s -> s.reverse())
.reduce(StringBuilder::append)
.map(StringBuilder::toString)
.get();
System.out.println(revertText);

public class Alternative {
public static void main(String[] args) {
Scanner robo = new Scanner(System.in);
System.out.println("Enter a word ");
String word = robo.nextLine();
char[] array = word.toCharArray();
int count = -1;
for (int i = 0; i < array.length; i++) {
if (Character.isUpperCase(array[i])) { //find the upper case letters in the word
for (int j = i; j > count; j--) //loop through the letters until the last count variable value is encountered
System.out.print(array[j]); //print the reversed values
count = i; //assign the last encountered uppercase letter's index value to count variable
}
}
}
}

why does "ig" repeat twice?

I was given to code something similar to piglatin. But I am getting the "ig" of pig in latin. What is wrong with the code?
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
String str = s.nextLine();
String end = "ay";
int i, j;
String word = "";
String[] arr = str.split(" ");
for (j = 0; j < arr.length; j++) {
String indWord = arr[j];
char c = indWord.charAt(0);
for (i = 1; i < indWord.length(); i++) {
word = word + indWord.charAt(i);
}
String res = "";
res = word + c + end + " ";
System.out.print(res);
}
}
}
Axpected:
pig latin ----> igpay atinlay
Actual:

Because you are not clearing the word variable for each iteration... that was hard to see because your indentation is wrong.
Move the String word=""; line to the inside of the for(j=0;j<arr.length;j++){ loop so that the word variable is cleared for every word and you start over (instead of carrying its contents from the last word)

swapping two letters in an unknown string in java

i am writing a program that must scramble a word. First I read in the word backwards using .reverse. Then I turned the string into a charArray.I am suppose to create a for loop to figure out if the First letter is "A" and if it is then i have to see if the next letter is not an "A". if its not then i am suppose to swap the two letters. If any of the two letters have a;ready been swapped than they cannot be swapped again.
Some examples are
Input: “TAN” Output: “ATN”
Input: “ALACTRIC” Output:“AALCTRIC”
Input: "Fork" Output:"Fork"
Here is my code so far: i cannot figure out what to put in the for loop. Thank you!
import java.util.Scanner;
public class scrambleWordRetry {
public static void main(String[] args)
{
}
public static String scramble( Random random, String inputString)
{
Scanner scan = new Scanner(System.in);
System.out.println("Please enter a word to scramble.");
inputString = scan.nextLine();
char a[] = inputString.toCharArray();
for( int i=0 ; i<a.length-1 ; i++ )
{
}
return inputString;
}
}

I hope this code is useful for you
Scanner x = new Scanner(System.in);
String str = x.next();
System.out.println("Before Swapping" + str);
str = scramble(str);
System.out.println("After Swapping " + str);
}
public static String scramble(String inputString) {
char s[] = inputString.toCharArray();
for (int i = 1; i < s.length; i++) {
if (s[i] == 'A' || s[i] == 'a') {
char temp = s[i - 1];
s[i - 1] = s[i];
s[i] = temp;
}
}
return new String(s);
}
then if you input 'ALACTRIC' the output will be 'AALCTRIC',
'Tan = aTn',
'fork = fork'.

Why am I not getting output?

Given question is:
A string can contain only a, b or c. There cannot be 2 consecutive same character. First and last character cannot be same. Now given a string with ‘a’, ‘b’, ‘c’ or ‘?’. We need to find the string replacing ‘?’ that satisfy the above conditions. For multiple answer display lexicographically smallest string. For no answer possible display “Not Possible”.
import java.util.*;
class Replace {
public static void main(String args[]) {
char[] arr = { 'a', 'b', 'c' };
char Pre, Suc;
Scanner in = new Scanner(System.in);
String str = new String();
String str2 = new String();
System.out.println("Enter the String");
while (in.hasNextLine()) {
str = in.nextLine();
}
for (int i = 0; i < str.length(); i++) {
if (str.charAt(i) == '?') {
Pre = str.charAt(i - 1);
Suc = str.charAt(i + 1);
for (int j = 0; j < 3; i++) {
while (arr[j] != Pre && arr[j] != Suc) {
str2 = str.substring(0, i) + arr[j]
+ str.substring(i + 1, (str.length() - 1));
}
}
}
}
System.out.println(str2);
}
}
The code is compiling without any errors. I still have to add a couple of things to the code as per question but I was trying to check if the code was correct so far but I am not getting any Output. Any tips/suggestions to improve the code is welcome.

The code Pre = str.charAt(i-1); and Suc = str.charAt(i+1); is problematic when "?" is the first/ last letter. It will cause then a java.lang.StringIndexOutOfBoundsException
At present you are not leaving the while-loop used for reading the input, hence System.out.println(str2); is never reached.

The problem is the program gets stuck in your while(in.hasNextLine()) { str = in.nextLine(); } loop. There is no exit condition. hasNextLine will block until a new line is entered. As per the Javadoc:
This method may block while waiting for input.

You need a condition to break the first while loop. When the user insert the input string he press enter, so the Scanner get the second input as an empty string. You could check the empty string and exit from the while loop.
import java.util.*;
class Replace
{
public static void main(String[] args)
{
char[] arr = {'a','b','c'};
char Pre,Suc;
Scanner in = new Scanner(System.in);
String str = new String();
String str2 = new String();
System.out.println("Enter the String");
while(in.hasNextLine())
{
if(str.isEmpty()) break;
str = in.nextLine();
}
for(int i=0;i<str.length();i++)
{
if(str.charAt(i)=='?')
{
Pre = str.charAt(i-1);
Suc = str.charAt(i+1);
for(int j=0;j<3;i++)
{
while(arr[j]!=Pre && arr[j]!=Suc)
{
str2 = str.substring(0,i)+arr[j]+str.substring(i+1,(str.length()-1));
}
}
}
}
System.out.println(str2);
}
}

Digit Frequency In A String

I am supposed to do this :
For an input number print frequency of each number in the order of its occurrence.For eg :
Input:56464
Output:
Number-Frequency
5 -1
6 -2
4 -2
I cannot use any other libraries except java.lang and Scanner to input
So I tried this :
package practice2;
import java.util.Scanner;
public class DigitFrequency2
{
private static Scanner sc;
public static void main(String[] args)
{
sc = new Scanner(System.in);
System.out.println("Enter an integer number");
String sb = sc.nextLine();
System.out.println("Number\tFrequency");
int i,x,c = 0;
for(i=0;i<sb.length();i++)
{
c = 0;
for(x = i+1;x<sb.length();x++)
{
if(sb.charAt(i) == sb.charAt(x) && sb.charAt(i) != '*' && sb.charAt(x) != '*')
{
c++;
sb.replace(sb.charAt(x),'*');
}
}
if(c>0)
{
System.out.println(sb.charAt(i)+" \t"+c);
}
}
}
}
Number Frequency
6 1
4 1
Where am I going wrong please help.

Simple way is this. Won't bother commenting as it is clear whats going on.
Scanner in = new Scanner(System.in);
while (true) {
System.out.print("Input String: ");
String line = in.nextLine();
while (!line.isEmpty()) {
char c = line.charAt(0);
int length = line.length();
line = line.replace(String.valueOf(c), "");
System.out.println(c + " " + (length - line.length()));
}
}

There are few problems with sb.replace(sb.charAt(x),'*');:
replace replaces all characters, not just first one which is why your c can't be grater than 1.
Strings are immutable so since replace can't edit original string, it returns new one with replaced characters which you can store back in sb reference.
Anyway if you would be able to use other Java resources beside java.lang.* or java.util.Scanner simple approach would be using Map which will map character with number of its occurrences. Very helpful here is merge method added in Java 8 allows us to pass key initialValue combination of old and new value
So your code can look like:
String sb = ...
Map<Character, Integer> map = new TreeMap<>();
for (char ch : sb.toCharArray()) {
map.merge(ch, 1, Integer::sum);
}
map.forEach((k, v) -> System.out.println(k + "\t" + v));

Problem is that as mentioned, String is immutable, so String.replace() just returns a new string and it does not (cannot) modify the original. Either you should use StringBuilder, or store the returned value (e.g. sb = sb.replace(sb.charAt(x),'*');).
Going further, since you initialize c with 0, it will stay 0 if there is no other occurrence of the character in question (sb.charAt(i)), so your algorithm won't detect and print digits that occur only once (because later you only print if c > 0).
Counting occurrences (frequency) of characters or digits in a string is a simple operation, it does not require to create new strings and it can be done by looping over the characters only once.
Here is a more efficient solution (one of the fastest). Since digits are in the range '0'..'9', you can create an array in which you count the occurrences, and by looping over the characters only once. No need to replace anything. Order of occurrence is "remembered" in another order char array.
char[] order = new char[10];
int[] counts = new int[10];
for (int i = 0, j = 0; i < sb.length(); i++)
if (counts[sb.charAt(i) - '0']++ == 0)
order[j++] = sb.charAt(i); // First occurrence of the digit
And print in order, until the order array is filled:
System.out.println("Number\tFrequency");
for (int i = 0; order[i] != 0; i++)
System.out.println(order[i] + "\t" + counts[order[i] - '0']);
Example output:
Enter an integer number
56464
Number Frequency
5 1
6 2
4 2
For completeness here's the complete main() method:
public static void main(String[] args) {
System.out.println("Enter an integer number");
String sb = new Scanner(System.in).nextLine();
char[] order = new char[10];
int[] counts = new int[10];
for (int i = 0, j = 0; i < sb.length(); i++)
if (counts[sb.charAt(i) - '0']++ == 0)
order[j++] = sb.charAt(i); // First occurrence of the digit
System.out.println("Number\tFrequency");
for (int i = 0; order[i] != 0; i++)
System.out.println(order[i] + "\t" + counts[order[i] - '0']);
}
Note:
If you would want to make your code safe against invalid inputs (that may contain non-digits), you could use Character.isDigit(). Here is only the for loop which is safe against any input:
for (int i = 0, j = 0; i < sb.length(); i++) {
char ch = sb.charAt(i);
if (Character.isDigit(ch)) {
if (counts[ch - '0']++ == 0)
order[j++] = ch; // First occurrence of ch
}
}

This should be a good code to print frequency using user input:
public static void main(String args[])
{
System.out.println("Please enter numbers ");
String time = in.nextLine(); //USER INPUT
time = time.replace(":", "");
char digit[] = {time.charAt(0), time.charAt(1), time.charAt(2), time.charAt(3)};
int[] count = new int[digit.length];
Arrays.sort(digit);
for (int i = 0; i < digit.length; i++)
{
count[i]++;
if (i + 1 < digit.length)
{
if (digit[i] == digit[i + 1])
{
count[i]++;
i++;
}
}
}
for (int i = 0; i < digit.length; i++)
{
if (count[i] > 0)
{
System.out.println(digit[i] + " appears " + count[i]+" time(s)");
}
}
}