public class x_at_end_ofString {

public static void main(String[] args) {

String s = "axbxcxdxexxxr";

String ns = "";

xAtEnd(s, 0, 0, ns);

}

public static void xAtEnd(String str,int idx,int count,String newString){

if(idx == str.length()){

for (int i = 0; i < count; i++) {

newString+='x';

}

System.out.println("count of x : "+count);

System.out.println(newString);

return;

}

char currChar = str.charAt(idx);

if(currChar == 'x'){

count++;

xAtEnd(str, idx+1, count, newString);

}else{

newString+=currChar;

xAtEnd(str, idx+1, count, newString);

}

}

}