Course exercises

Collection_Ex.kt

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+fun main() {
+    val words = listOf("Kotlin", "is", "awesome", "for", "Android", "development")
+
+    // Step 1
+    val wordLengths = words.associateWith { it.length }
+
+    // Step 2
+    wordLengths.filter { it.value > 4 }.forEach { (word, length) ->
+        println("$word has $length letters")
+    }
+}

Data_Processing_Ex.kt

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+data class Student(val name: String, val age: Int, val score: Int)
+
+fun List<Student>.averageScore(): Double =
+        if (isEmpty()) 0.0 else sumOf { it.score }.toDouble() / size
+
+fun processStudents(students: List<Student>, action: (Student) -> Unit) {
+    students.forEach(action)
+}
+
+fun main() {
+    val students =
+            listOf(
+                    Student("Alice", 20, 85),
+                    Student("Bob", 21, 92),
+                    Student("Jeff", 19, 78),
+                    Student("Sara", 22, 95),
+                    Student("Mike", 20, 65)
+            )
+
+    // students with score >= 80
+    students.filter { it.score >= 80 }.map { it.name }.forEach { println("Good student: $it") }
+
+    println("\nProcessing all students:")
+    processStudents(students) { student ->
+        println("${student.name} (${student.age}) scored ${student.score}")
+    }
+
+    println("\nAverage score of all students: ${students.averageScore()}")
+}

Higher_Order_Ex.kt

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+import kotlin.*
+
+fun processList(numbers: List<Int>, predicate: (Int) -> Boolean): List<Int> =
+        numbers.filter(predicate) 
+
+fun main() {
+    val numbers = listOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
+
+    // Example 1: keep only even numbers
+    val evenNumbers = processList(numbers) { it % 2 == 0 }
+    println("Even: $evenNumbers") 
+
+    // Example 2: keep only numbers > 5
+    val bigNumbers = processList(numbers) { it > 5 }
+    println("Big: $bigNumbers") 
+}