Accept a sentence and print the words that have same consecutive characters

Question

Here is my homework:

accept a sentence and print the words that have consecutive characters equal

INPUT: an apple a day keeps

OUTPUT: apple keeps

Here is what I am working on:

import java.util.*;

public class Program1
{
    public static void main(String args[]) 
    {
        Scanner sc=new Scanner(System.in);
        System.out.println("Enter a sentence");
        String s=sc.nextLine();
        String str=s.toLowerCase(); 
        int l,i=0; char c,d;int a,b,m=0;int n=0; String r=""; String res="";
        l=s.length();
        str=" "+str+" ";
        for(i=0;i<(l-1);i++)
        {
            c=str.charAt(i);
            d=str.charAt(i+1);
            a=c;
            b=d;
            m=str.indexOf(' ');
            n=str.indexOf(' ',(i+1)); 
             if(d==' ')
              { 
               m=str.indexOf(' ',(i-1));
               n=str.indexOf(' ',(i+1));
            }  
            if(a==b)
             {
               r=str.substring(m,n);
               res=res +" "+ r;
              }
            
         }
         System.out.println(res);
     }
}

It gets compiled, but it does not give correct output.

If I enter the above example, it returns:

an apple   an apple a day keeps

What do I need to do?

Answer 1

You can do something like this to achieve the result,

Scanner sc = new Scanner(System.in);
System.out.println("Enter a sentence");
String s = sc.nextLine();
String str = s.toLowerCase();
String[] words = str.split(" ");   // Split the sentence into an array of words.

for(String ss : words){
    char previousChar = '\u0000';
    for (char c : ss.toCharArray()) {
        if (previousChar == c) {    // Same character has occurred
            System.out.println(ss);
            break;
        }
        previousChar = c;
    }
}