Creating a string, reversing it, and than comparing with another one

Question

// get input
InputStreamReader is = new InputStreamReader (System.in);
BufferedReader in = new BufferedReader (is);
String str = in.readLine ();
// get length of input
int len = str.length ();
// reverse the input
//String rts = "";// = new String[len];
//for (int i=0; i<len; i++) rts.concat (str.charAt (len - i));
StringBuffer rts = new StringBuffer(str).reverse ();
// display the reversed string
System.out.println(rts + "\n");
// end if input was "tiuq"
if (rts == "quit") break;I am accustomed to C language, now trying to learn Java. The string operations are still too much for me.
In the code above, I managed to reverse my string using a "StringBuffer" object (still i don't know what it is), but couldn't compare it with "quit" constant. Compiler give "imcompareble types" error message.
*1) How can I compare a StringBuffer with a constant?*
On the other hand, why didn't my for loop didn't work (the commented-out one)? This time compiler says "java.lang.String cannot be applied to (char)".
*2) How can I make this method work?*
I also tried something like this:String[] rts = new String[len];
for (int i=0; i<len; i++) rts[i] = str[len - i];But in this way, I couldn't find a way to compare str with the constant "quit".
*3) How can I compare a String with a constant?*
Can someone answer help me out on these 3 questions?

Answer 1

hkBattousai wrote:
@Skydev2u
Why did you use nested fors? It can already be done with only one for loop. I didn't understand your logic.
Anyway, my code works, and it is as follows:// get input
InputStreamReader is = new InputStreamReader (System.in);
BufferedReader in = new BufferedReader (is);
String str = in.readLine ();
// get length of input
int len = str.length ();
// reverse the input
StringBuffer rts = new StringBuffer(str).reverse ();
// display the reversed string
System.out.println(rts + "\n");
// end if input was "tiuq"
if (rts.toString().equals("quit")) break;What I want to learn is, isn't a way to realize this without using that StringBuffer thing? Can you propose a mathod that merely uses the String class?I used the nested loops because I thought it would make the code clearer but at the same time i didn't really understand what you were doing since I don't know much about StringBuffer class. But from your reply I see that it was not needed.
(The above stated is my best understanding of the concept. Use it as a guideline to answering your question)