[refactor] 외부에서 필드 값 변경으로 인한 사이드 이팩트 발생 가능성 고려

- 외부에서 클래스 내의 필드 값 변경하지 않도록 수정
- 필드를 생성하지 않고 단순히 strike와 ball 계산 후 값 return

baseball_game/src/main/java/Game/Answer.java

@@ -33,12 +33,9 @@ public Boolean checkAnswer(int guess) {
         int tens = (answerNumber/10)%10;
         int hundreds = answerNumber/100;
 
-        // strike 수 세기
-        Evaluate.countStrike(guess, hundreds, tens, units);
-        Evaluate.countBall(guess, hundreds, tens, units);
-
-        int strike = Evaluate.getStrike();
-        int ball = Evaluate.getBall();
+        // strike, ball 수 세기
+        int strike = Evaluate.countStrike(guess, hundreds, tens, units);
+        int ball = Evaluate.countBall(guess, hundreds, tens, units);
 
         if(strike==0 && ball==0) {
             System.out.print("낫싱\n");

baseball_game/src/main/java/Game/Evaluate.java

@@ -1,35 +1,22 @@
 package Game;
 
 public class Evaluate {
-    private int inputNumber;
-    private static int strike;
-    private static int ball;
+    public Evaluate(int guess, int answer) {}
 
-    public Evaluate(int guess, int answer) {
-
-    }
-
-    public static int getStrike() {
-        return strike;
-    }
-    public static int getBall() {
-        return ball;
-    }
-
-    public static void countStrike(int guess, int hundreds, int tens, int units) {
+    public static int countStrike(int guess, int hundreds, int tens, int units) {
         int strikeN = 0;
         if(guess%10 == units) strikeN++;
         if((guess/10)%10 == tens) strikeN++;
         if(guess/100 == hundreds) strikeN++;
-        strike = strikeN;
+        return strikeN;
     }
 
-    public static void countBall(int guess, int hundreds, int tens, int units) {
+    public static int countBall(int guess, int hundreds, int tens, int units) {
         int ballN = 0;
         if((guess%10==hundreds) || (guess%10==tens)) ballN++;
         if(((guess/10)%10==hundreds) || ((guess/10)%10==units)) ballN++;
         if((guess/100==tens) || (guess/100==units)) ballN++;
-        ball = ballN;
+        return ballN;
     }
 
 }