Kotlin Puzzlersの紹介

Osaka Mix Leap Study 11の発表資料です．

Transcript

1.  
   
2. 
   • Y • , JOKMI • • • HE P B • ! ,&,! A ! • ! ! 2 SX
4. ʁ
5. > ʁ
6.  
       
7. 
   
8. 
    println(127 as Int? === 127 as Int?) println(128 as Int? === 128 as Int?) // a) true; true // b) false; false // c) true; false // d) ↑
   
9. 
    println(127 as Int? === 127 as Int?) println(128 as Int? === 128 as Int?) // a) true; true // b) false; false // c) true; false // d) ↑
   
   
10. 
     println(127 as Int? === 127 as Int?) println(128 as Int? === 128 as Int?) Int?
    
11. 
     println(127 as Int? === 127 as Int?) println(128 as Int? === 128 as Int?) Int  →  Int? → null  Int? →     Int?
    
12. 
     println(127 as Int? === 127 as Int?) println(128 as Int? === 128 as Int?) Int?  
       Int? 
13. 
     println(127 as Int? === 127 as Int?) println(128 as Int? === 128 as Int?) ===
     
          
14. 
     println(127 as Int? === 127 as Int?) println(128 as Int? === 128 as Int?) // a) true; true // b) false; false // c) true; false // d) ↑
    b) …? 
    
15. 
     - 8 8 - 1 27 println(127 as Int? === 127 as Int?) println(128 as Int? === 128 as Int?) 127,128-
16. 
     7 8 -1 println(127 as Int? === 127 as Int?) println(128 as Int? === 128 as Int?) 127 128 , 7 2 true
17. 
     78 7 1 -2 println(127 as Int? === 127 as Int?) println(128 as Int? === 128 as Int?) 127 128 1 - 78 7 false , 78 7 true
18. 
     println(127 as Int? === 127 as Int?) println(128 as Int? === 128 as Int?) // a) true; true // b) false; false // c) true; false // d) ↑ 
    false true
19. & // ↓ int i = 1; // ↓   Integer i = new Integer(1); // ↓  Integer i = 1; // ↓ val i: Int = 1 // ↓  val i: Int? = 1
      
20. & // ↓ int i = 1; // ↓   Integer i = new Integer(1); // ↓  Integer i = 1; // ↓ val i: Int = 1 // ↓  val i: Int? = 1
      
21. & // ↓ int i = 1; // ↓   Integer i = new Integer(1); // ↓  Integer i = 1; // ↓ val i: Int = 1 // ↓  val i: Int? = 1
      
22. & // ↓ int i = 1; // ↓   Integer i = new Integer(1); // ↓  Integer i = 1; // ↓ val i: Int = 1 // ↓  val i: Int? = 1
      
23.     
     Integer a127 = 127; Integer b127 = 127; // 
     Integer a128 = 128; Integer b128 = 128; System.out.println(a127 == b127); // true System.out.println(a128 == b128); // false
24.     
     Integer a127 = 127; Integer b127 = 127; // 
     Integer a128 = 128; Integer b128 = 128; System.out.println(a127 == b127); // true System.out.println(a128 == b128); // false
25.     
     Integer a127 = 127; Integer b127 = 127; // 
     Integer a128 = 128; Integer b128 = 128; System.out.println(a127 == b127); // true System.out.println(a128 == b128); // false
26.     
     Integer a127 = 127; Integer b127 = 127; // 
     Integer a128 = 128; Integer b128 = 128; System.out.println(a127 == b127); // true System.out.println(a128 == b128); // false
27.     
     Integer a127 = new Integer(127); Integer b127 = new Integer(127); //
      Integer a128 = new Integer(128); Integer b128 = new Integer(128); System.out.println(a127 == b127); // false System.out.println(a128 == b128); // false
28.     
     Integer a127 = new Integer(127); Integer b127 = new Integer(127); //
      Integer a128 = new Integer(128); Integer b128 = new Integer(128); System.out.println(a127 == b127); // false System.out.println(a128 == b128); // false
29. 
    
30. 
     enum class E { e } val e = E.e val a = when (E.e) { e -> "1" } print(a) // a) 1 // b) null // c) NullPointerException // d) 
    
31. 
     enum class E { e } val e = E.e val a = when (E.e) { e -> "1" } print(a) // a) 1 // b) null // c) NullPointerException // d) 
    
32. 
     enum class E { e } val e = E.e val a = when (E.e) { e -> "1" } print(a) // a) 1 // b) null // c) NullPointerException // d) 
    
33. 
     enum class E { e } val e = E.e val a = when (E.e) { e -> "1" } print(a) // a) 1 // b) null // c) NullPointerException // d) 
    
34. 
     enum class E { e } val e = E.e val a = when (E.e) { e -> "1" } print(a) // a) 1 // b) null // c) NullPointerException // d) 
    
35. 
     enum class E { e } val e = E.e val a = when (E.e) { e -> "1" } print(a) // a) 1 // b) null // c) NullPointerException // d) 
    
    
36. 
     enum class E { e } val e = E.e val a = when (E.e) { e -> "1" } print(a) 
         
    
37.   
     
    
38. 2 &  when 
        enum class E { e1, e2 } val a = when (E.e1) { E.e1 -> "1" } print(a) 
    
39. 2 & 
         
     enum class E { e1, e2 } val a = when (E.e1) { E.e1 -> "1" E.e2 -> "2" } print(a)
40. 
     enum class E { e } val e = E.e val a = when (E.e) { e -> "1" } print(a)    
    
    
41. 
     enum class E { e } val e = E.e val a = when (E.e) { e -> "1" } print(a) 
         
    
42. 
     enum class E { e } val a = when (E.e) { E.e -> "1" } print(a) 
     
43. 
     enum class E { e } val e = E.e val a = when (E.e) { e -> "1" } print(a) enum E { case e } let eVar = E.e switch E.e { case eVar: print("a") } 
    
       
    
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      66 2 6 / . 6 -1 20 -
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46. 
     val s: String? = null if (s?.isEmpty()) println("true") // a) Nothing // b) true // c) NullPointerException // d) 
    
47. 
     val s: String? = null if (s?.isEmpty()) println("true") // a) Nothing // b) true // c) NullPointerException // d) 
    
48. 
     val s: String? = null if (s?.isEmpty()) println("true") // a) Nothing // b) true // c) NullPointerException // d) 
    
49. 
     val s: String? = null if (s?.isEmpty()) println("true") // a) Nothing // b) true // c) NullPointerException // d) 
    
    
50. 
     val s: String? = null if (s?.isEmpty()) println("true") s?null  isEmpty() 
    null  
    
51. 
     val s: String? = null if (s?.isEmpty()) println("true") // a) Nothing // b) true // c) NullPointerException // d)  
    
    
52. 
     val s: String? = null if (s?.isEmpty()) println("true") if null
       
    
53.  
     if (null) print(true) else print(false) // 
    
    
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     if (null) print(true) else print(false) //  
    
    
55. 
      if (null) console.log(true); else console.log(false); // false
    
56.  
     if None: print(True) else: print(False) # False
    
57.  
     if nil then print(true) else print(false) end # false
    
58.  
     if (null) echo true; else echo false; // false
    
59. 
     if (null) System.out.println(true); else System.out.println(false); 
    
60.  
     if nil { print(true) } else { print(false) } 
    
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    if (NULL) printf("true"); else printf("false"); // false
    
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     55 65 . - 5 / 6
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65. 
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