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トップJavaに関する質問星座の判別をIF文を大量に使わずに判別する方法

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回答編集履歴

2

MonthDay クラス使用

2019/10/15 14:19

投稿

jimbe
jimbe

スコア13202

test CHANGED
@@ -16,27 +16,23 @@
16
16
 
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  int day = Integer.parseInt(myDay.substring(2, 4));
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+ MonthDay monthDay = MonthDay.of(month, day);
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+
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  // 星座取得.
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- Zodiac constellation = Zodiac.get(month, day);
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+ Zodiac constellation = Zodiac.get(monthDay);
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-
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- if (constellation == null) {
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-
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- System.out.println("日付が正しくない");
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-
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- return;
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-
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- }
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24
 
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  System.out.println(constellation.getJName());
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- } catch (Exception e) {
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+ } catch (DateTimeException e) {
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28
 
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  System.out.println("日付が正しくない");
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30
 
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31
  }
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39
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  }
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+
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+
40
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  enum Zodiac {
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38
 
@@ -58,7 +54,15 @@
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  Sagittarius("射手座", 11,23, 12,21),
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56
 
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- Capricornus("山羊座", 12,22, 1,19),
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+ Capricornus("山羊座", 12,22, 1,19) {
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+
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+ boolean contains(MonthDay target) { //年をまたがるのでこれだけ式が違う
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+
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+ return start.compareTo(target) <= 0 || target.compareTo(end) <= 0;
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+
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+ }
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+
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+ },
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  Aquarius("水瓶座", 1,20, 2,18),
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68
 
@@ -66,43 +70,35 @@
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- private String jname;
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+ protected String jname;
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- private int startMonth, startDay;
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+ protected MonthDay start, end;
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-
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- private int endMonth, endDay;
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77
  Zodiac(String jname, int startMonth, int startDay, int endMonth, int endDay) {
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  this.jname = jname;
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80
 
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- this.startMonth = startMonth;
81
+ this.start = MonthDay.of(startMonth, startDay);
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82
 
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- this.startDay = startDay;
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-
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- this.endMonth = endMonth;
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+ this.end = MonthDay.of(endMonth, endDay);
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-
85
- this.endDay = endDay;
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  }
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89
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  String getJName() { return jname; }
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88
 
91
- boolean contains(int month, int day) {
89
+ boolean contains(MonthDay target) {
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- return (startMonth == month && startDay <= day || endMonth == month && endDay >= day);
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+ return start.compareTo(target) <= 0 && target.compareTo(end) <= 0;
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92
 
95
93
  }
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94
 
97
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98
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99
- static Zodiac get(int month, int day) {
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+ static Zodiac get(MonthDay target) {
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98
 
101
- if(month < 1 || month > 12 || day < 1 || day > 31) throw new IllegalArgumentException("month="+month+",day="+day);
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+ for(Zodiac z : values()) if(z.contains(target)) return z;
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100
 
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- for(Zodiac z : values()) if(z.contains(month, day)) return z;
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+ throw new DateTimeException("定義に洩れがあるようです. target="+target);
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-
105
- return null;
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102
 
107
103
  }
108
104
 

1

メソッド追加

2019/10/15 14:19

投稿

jimbe
jimbe

スコア13202

test CHANGED
@@ -88,19 +88,19 @@
88
88
 
89
89
  String getJName() { return jname; }
90
90
 
91
+ boolean contains(int month, int day) {
92
+
93
+ return (startMonth == month && startDay <= day || endMonth == month && endDay >= day);
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+
95
+ }
96
+
91
97
 
92
98
 
93
99
  static Zodiac get(int month, int day) {
94
100
 
95
101
  if(month < 1 || month > 12 || day < 1 || day > 31) throw new IllegalArgumentException("month="+month+",day="+day);
96
102
 
97
- for(Zodiac z : values()) {
98
-
99
- if(z.startMonth == month && z.startDay <= day ||
100
-
101
- z.endMonth == month && z.endDay >= day) return z;
103
+ for(Zodiac z : values()) if(z.contains(month, day)) return z;
102
-
103
- }
104
104
 
105
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  return null;
106
106