Reverse every word in a string and capitalize the start of the word

Question

Sample input:

abc def ghi

Sample output:

Cba Fed Ihg

This is my code:

import java.util.Stack;

public class StringRev {
    static String output1 = new String();
    static Stack<Character> stack = new Stack<Character>();
    public static void ReverseString(String input) {
        input = input + " ";
        for (int i = 0; i < input.length(); i++) {
            boolean cap = true;
            if (input.charAt(i) == ' ') {
                while (!stack.isEmpty()) {
                    if (cap) {
                        char c = stack.pop().charValue();
                        c = Character.toUpperCase(c);
                        output1 = output1 + c;
                        cap = false;
                    } else
                        output1 = output1 + stack.pop().charValue();
                }
                output1 += " ";
            } else {
                stack.push(input.charAt(i));
            }
        }
        System.out.print(output1);
    }
}

Any better solutions?

Solution 1

Make use of

StringBuilder#reverse()

Then without adding any third party libraries,

    String originalString = "abc def ghi";
    StringBuilder resultBuilder = new StringBuilder();
    for (String string : originalString.split(" ")) {
        String revStr = new StringBuilder(string).reverse().toString();
        revStr = Character.toUpperCase(revStr.charAt(0))
                + revStr.substring(1);
        resultBuilder.append(revStr).append(" ");
    }
    System.out.println(resultBuilder.toString());  //Cba Fed Ihg 

Have a Demo

Solution 2

You can use the StringBuffer to reverse() a string.

And then use the WordUtils#capitalize(String) method to make first letter of the string capitalized.

String str = "abc def ghi";
StringBuilder sb = new StringBuilder();
for (String s : str.split(" ")) {
    String revStr = new StringBuffer(s).reverse().toString();
    sb.append(WordUtils.capitalize(revStr)).append(" ");
}
String strReversed = sb.toString();

Solution 3

1) Reverse the String with this

StringBuffer a = new StringBuffer("Java");
a.reverse();

2) To make First letter capital use StringUtils class in apache commons lang package org.apache.commons.lang.StringUtils

It makes first letter capital

capitalise(String);

Hope it helps.

Solution 4

public static String reverseString(final String input){
    if(null == input || isEmpty(input))
        return "";

    String result = "";
    String[] items = input.split(" ");

    for(int i = 0; i < items.length; i++){
        result += new StringBuffer(items[i]).reverse().toString();
    }

    return result.substring(0,1).toupperCase() + result.substring(1);
}

Solution 5

Edited

Reverse the string first and make the first character to uppercase

String string="hello jump";
StringTokenizer str = new StringTokenizer(string," ") ;
String finalString ;

while (str.hasMoreTokens()) {
   String input = str.nextToken() ;
   String reverse = new StringBuffer(input).reverse().toString();
   System.out.println(reverse);

   String output = reverse .substring(0, 1).toUpperCase() + reverse .substring(1);
   finalString=finalString+" "+output ;
}

System.out.println(finalString);

View more solutions

Comments

[SpringLearner]

I think this question belows to codereview.stackexchange.com

[rtindru]

@javaBeginner Should I ask it there as well or can I move it to codeReview. Also Is this a good implementation?

[newuser]

Don't use String to concat the results. Use StringBuilder to append the result values. Because String is immutable. Remove the String variable output1 and create a StringBuilder with in the reverseMethod

[rtindru]

I think you didn't follow completely. Its not supposed to do abc to Cba. Rather its gotta do abc def to Cba Fed

[Arun]

Then you can tokenize the whole word and apply this above logic to each tokens.

[Arun]

Please mark my answer as correct one, if it is useful and simple to your requirement

[B-Y]

stdin is 3 line input, for example, input = "2", "dog", "Cat", and it requires stdout, output = "God", "TaC". How to do Scanner, do I need to use a list? Thank you so much!