integrating if statements into a for loop with

Question

I am making a Mastermind program.

I generate a random String with 4 numerical characters (characters cannot repeat themselves). For testing purposes, it's always 1234.

The user is then asked to guess the String by inputing 4 numbers.

I am making a method called PerfectMatches that checks how many guessed numbers are correct AND in the right position.

Here is my code :

public static int perfectMatches (String x, String y){
    int i = 0;
    int perfectmatches = 0;

    for (i=0; i < 4; i++){
        if ((x.charAt(i)) == (y.charAt(i))){
            perfectmatches++;
        }

I tried using if statements but I felt it wasn't efficient and took longer to process for the program.

what is the problem? for only 4 lenght string how do you judge the performance :S — stinepike, Feb 28 '14 at 05:29
How long/slow is your program? That's just basic comparison right there. — Rey Libutan, Feb 28 '14 at 05:29
Performance decreased only because of the loop !! what about other code ? did you consider that ? — Not a bug, Feb 28 '14 at 05:30
@Alexander_Winter - because it won't tell you "how many" are correct". it will just tell if x is equal to y (boolean : true or false). — TheLostMind, Feb 28 '14 at 05:34
possible duplicate of [if else loop inside a for loop?](http://stackoverflow.com/questions/10147690/if-else-loop-inside-a-for-loop) — D3X, Feb 28 '14 at 05:41
Since you are accounting for the positions being correct I don't think there's a faster way to do it. You have to check the whole thing. — Radiodef, Feb 28 '14 at 05:57

score 0 · Answer 1 · answered Feb 28 '14 at 05:31

0

Since the length is 4, then performance doesn't matter in this case. I think perfectMatches() method should return a boolean:

public static boolean perfectMatches(String x, String y) {...}

Also, avoid magic numbers:

for (int i = 0; i < x.length(); i++)

And at the end you could compare perfectmatches with 4, and return the boolean (true or false):

return (perfectmaches == 4);

But if you would like to return the numbers of matches, then the way you did your method is fine. Just return perfectmatches. As and advice, you can change the name of perfectmatches since it is very similar to the name of the method perfectMatches()

answered Feb 28 '14 at 05:31

Christian Tapia

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"checks how many guessed numbers are correct AND in the right position." . Maybe he will give a score based on number of right guesses. He could do it in the perfectMatches() itself . But its better to do it in the parent, seperate calculating and dsplaying. right? – TheLostMind Feb 28 '14 at 05:33
1

Yes, or make another method, that uses the `int` returned by `perfectMatches() to compare with the length of the `String` and return a `boolean`. – Christian Tapia Feb 28 '14 at 05:34

score 0 · Answer 2 · answered Feb 28 '14 at 05:35

I don't think this could create any performance problem..

BTW, irrelevant to the question:

I have written the MasterMind application. You have to consider having the "numbers can't repeat" condition removed. It makes the game/puzzle easier, as well as the implementation.

If you want challenging puzzle as well the coding, allow duplication numbers. In that case, you will have to calculate both the perfect match and (match, but not in the same location) in a single method.

score 0 · Answer 3 · answered Feb 28 '14 at 05:39

0

There's no really a problem at it... it just check your code...

public int perfectMatches (String x, String y){ 
   int i = 0; 
   int perfectmatches = 0;

   for(i = 0; i < x.length(); i++){
      if(x.charAt(i) == y.charAt(i)){
          perfectmatches++;
      }
   }

   return perfectmatches;
}

another... remove the static...

answered Feb 28 '14 at 05:39

user2819448

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Why do you think the method shouldn't be static? – Radiodef Feb 28 '14 at 05:58

integrating if statements into a for loop with

3 Answers3