Resolutions

Author: svtk

src/i_introduction/_0_Hello_World/n00Start.kt

@@ -24,6 +24,4 @@ fun todoTask0(): Nothing = TODO(
     references = { task0(); "OK" }
 )
 
-fun task0(): String {
-    return todoTask0()
-}
+fun task0() = "OK"

src/i_introduction/_10_Object_Expressions/n10ObjectExpressions.kt

@@ -18,6 +18,8 @@ fun todoTask10(): Nothing = TODO(
 
 fun task10(): List<Int> {
     val arrayList = arrayListOf(1, 5, 2)
-    Collections.sort(arrayList, todoTask10())
+    Collections.sort(arrayList, object : Comparator<Int> {
+        override fun compare(x: Int, y: Int) = y - x
+    })
     return arrayList
 }

src/i_introduction/_11_SAM_Conversions/n11SAMConversions.kt

@@ -15,6 +15,6 @@ fun todoTask11(): Nothing = TODO(
 
 fun task11(): List<Int> {
     val arrayList = arrayListOf(1, 5, 2)
-    Collections.sort(arrayList, { x, y -> todoTask11() })
+    Collections.sort(arrayList, { x, y -> y - x })
     return arrayList
 }

src/i_introduction/_12_Extensions_On_Collections/n12ExtensionsOnCollections.kt

@@ -17,7 +17,6 @@ fun todoTask12(): Nothing = TODO(
 )
 
 fun task12(): List<Int> {
-    todoTask12()
-    return arrayListOf(1, 5, 2)
+    return arrayListOf(1, 5, 2).sortedDescending()
 }
 

src/i_introduction/_1_Java_To_Kotlin_Converter/n01JavaToKotlinConverter.kt

@@ -14,5 +14,16 @@ fun todoTask1(collection: Collection<Int>): Nothing = TODO(
 
 
 fun task1(collection: Collection<Int>): String {
-    todoTask1(collection)
+    val sb = StringBuilder()
+    sb.append("{")
+    val iterator = collection.iterator()
+    while (iterator.hasNext()) {
+        val element = iterator.next()
+        sb.append(element)
+        if (iterator.hasNext()) {
+            sb.append(", ")
+        }
+    }
+    sb.append("}")
+    return sb.toString()
 }

src/i_introduction/_2_Named_Arguments/n02NamedArguments.kt

@@ -24,6 +24,5 @@ fun todoTask2(): Nothing = TODO(
     references = { collection: Collection<Int> -> task1(collection); collection.joinToString() })
 
 fun task2(collection: Collection<Int>): String {
-    todoTask2()
-    return collection.joinToString()
+    return collection.joinToString(prefix = "{", postfix = "}")
 }

src/i_introduction/_3_Default_Arguments/n03DefaultArguments.kt

@@ -14,12 +14,12 @@ fun todoTask3(): Nothing = TODO(
     documentation = doc2(),
     references = { name: String -> JavaCode3().foo(name); foo(name) })
 
-fun foo(name: String): String = todoTask3()
+fun foo(name: String, number: Int = 42, toUpperCase: Boolean = false) =
+        (if (toUpperCase) name.toUpperCase() else name) + number
 
 fun task3(): String {
-    todoTask3()
-//    return (foo("a") +
-//            foo("b", number = 1) +
-//            foo("c", toUpperCase = true) +
-//            foo(name = "d", number = 2, toUpperCase = true))
+    return (foo("a") +
+            foo("b", number = 1) +
+            foo("c", toUpperCase = true) +
+            foo(name = "d", number = 2, toUpperCase = true))
 }

src/i_introduction/_4_Lambdas/n04Lambdas.kt

@@ -22,4 +22,4 @@ fun todoTask4(collection: Collection<Int>): Nothing = TODO(
     documentation = doc4(),
     references = { JavaCode4().task4(collection) })
 
-fun task4(collection: Collection<Int>): Boolean = todoTask4(collection)
+fun task4(collection: Collection<Int>): Boolean = collection.any { it % 2 == 0 }

src/i_introduction/_5_String_Templates/n05StringTemplates.kt

@@ -35,4 +35,4 @@ fun todoTask5(): Nothing = TODO(
     documentation = doc5(),
     references = { getPattern(); month })
 
-fun task5(): String = todoTask5()
+fun task5(): String = """\d{2} $month \d{4}"""

src/i_introduction/_6_Data_Classes/n06DataClasses.kt

@@ -15,10 +15,10 @@ fun todoTask6(): Nothing = TODO(
     references = { JavaCode6.Person("Alice", 29) }
 )
 
-class Person
+data class Person(val name: String, val age: Int)
 
 fun task6(): List<Person> {
-    todoTask6()
-    return listOf(/*Person("Alice", 29), Person("Bob", 31)*/)
+//    todoTask6()
+    return listOf(Person("Alice", 29), Person("Bob", 31))
 }