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doc: update docs/kotlin.md

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@ -17,6 +17,7 @@ fun main() {
main() 函数是每个 Kotlin 程序的起点，在执行之前必须包含在代码中 main() 函数是每个 Kotlin 程序的起点，在执行之前必须包含在代码中
### 打印声明 ### 打印声明
<!--rehype:wrap-class=row-span-2-->
```kotlin ```kotlin
println("Greetings, earthling!") println("Greetings, earthling!")
@ -31,6 +32,7 @@ Take me to your leader.
``` ```
### 注释 ### 注释
<!--rehype:wrap-class=row-span-2-->
```kotlin ```kotlin
// 这是单行注释 // 这是单行注释
@ -109,7 +111,7 @@ println(monument.length)
``` ```
### 字符转义序列 ### 字符转义序列
<!--rehype:wrap-class=row-span-2--> <!--rehype:wrap-class=row-span-3-->
```kotlin ```kotlin
print("\"Excellent!\" I cried. \"Elementary,\" said he.") print("\"Excellent!\" I cried. \"Elementary,\" said he.")
@ -149,6 +151,7 @@ print("\"Excellent!\" I cried. \"Elementary,\" said he.")
``` ```
### 增强赋值运算符 ### 增强赋值运算符
<!--rehype:wrap-class=row-span-2-->
```kotlin ```kotlin
var batteryPercentage = 80 var batteryPercentage = 80
@ -267,6 +270,7 @@ println(shorts && sunny) // false
``` ```
### 或运算符：|| ### 或运算符：||
<!--rehype:wrap-class=row-span-2-->
```kotlin ```kotlin
var late = true var late = true
@ -295,6 +299,7 @@ println(!full) // true
``` ```
### 评估顺序 ### 评估顺序
<!--rehype:wrap-class=row-span-2-->
```kotlin ```kotlin
!true && (false || true) // false !true && (false || true) // false
@ -311,6 +316,16 @@ println(!full) // true
*/ */
``` ```
### 等式运算符
```kotlin
var myAge = 22
var sisterAge = 21
myAge == sisterAge // false
myAge !== sisterAge // true
```
### 嵌套条件 ### 嵌套条件
```kotlin ```kotlin
@ -356,16 +371,6 @@ if (height in 1..53) {
``` ```
<!--rehype:className=wrap-text--> <!--rehype:className=wrap-text-->
### 等式运算符
```kotlin
var myAge = 22
var sisterAge = 21
myAge == sisterAge // false
myAge !== sisterAge // true
```
Collections Collections
--- ---
@ -608,10 +613,11 @@ fun main() {
### 简单的高阶函数 ### 简单的高阶函数
<!--rehype:wrap-class=col-span-2--> <!--rehype:wrap-class=col-span-2-->
```kotlin ```kotlin
//注意啦，这里的num1AndNum2有个operation，它是接收了一个函数作为形参 // 注意啦，这里的 num1AndNum2 有个 operation，它是接收了一个函数作为形参
fun num1AndNum2(num1: Int, num2: Int, operation: (Int, Int) -> Int): Int { fun num1AndNum2(num1: Int, num2: Int, operation: (Int, Int) -> Int): Int {
//让我们试着向operation传入参数 // 让我们试着向 operation 传入参数
return operation(num1, num2) return operation(num1, num2)
} }
@ -622,14 +628,11 @@ fun plus(num1: Int, num2: Int): Int {
fun main(args: Array<String>) { fun main(args: Array<String>) {
val total = num1AndNum2(100, 200, ::plus) val total = num1AndNum2(100, 200, ::plus)
println(total)//300 println(total)//300
//怎么样？我们利用传入一个函数来充当另一个函数的参数 // 怎么样？我们利用传入一个函数来充当另一个函数的参数
} }
``` ```
还记得我们怎么在Java中用接口吗？ 还记得我们怎么在 Java 中用接口吗？试着用函数参数简化它
试着用函数参数简化它
<!--rehype:className=wrap-text--> <!--rehype:className=wrap-text-->
@ -678,20 +681,6 @@ fun main(args: Array<String>) {
类 类
--- ---
### 类示例
```kotlin
// 具有包含默认值的属性的类
class Student {
var name = "Lucia"
var semester = "Fall"
var gpa = 3.95
}
// 没有类体的简写语法
class Student
```
### 类实例 ### 类实例
```kotlin ```kotlin
@ -715,6 +704,7 @@ fun main() {
``` ```
### 主构造函数 ### 主构造函数
<!--rehype:wrap-class=col-span-2-->
```kotlin ```kotlin
class Student(val name: String, val gpa: Double, val semester: String, val estimatedGraduationYear: Int) class Student(val name: String, val gpa: Double, val semester: String, val estimatedGraduationYear: Int)
@ -733,24 +723,22 @@ fun main() {
``` ```
<!--rehype:className=wrap-text--> <!--rehype:className=wrap-text-->
### 初始化块 ### 类示例
```kotlin ```kotlin
class Student(val name: String, val gpa: Double, val semester: String, val estimatedGraduationYear: Int) { // 具有包含默认值的属性的类
init { class Student {
println("$name has ${estimatedGraduationYear - 2020} years left in college.") var name = "Lucia"
} var semester = "Fall"
var gpa = 3.95
} }
fun main() { // 没有类体的简写语法
var student = Student("Lucia", 3.95, "Fall", 2022) class Student
// Prints: Lucia has 2 years left in college.
}
``` ```
<!--rehype:className=wrap-text-->
### 成员函数 ### 成员函数
<!--rehype:wrap-class=col-span-2--> <!--rehype:wrap-class=col-span-2 row-span-2-->
```kotlin ```kotlin
class Student(val name: String, val gpa: Double, val semester: String, val estimatedGraduationYear: Int) { class Student(val name: String, val gpa: Double, val semester: String, val estimatedGraduationYear: Int) {
@ -781,6 +769,22 @@ fun main() {
``` ```
<!--rehype:className=wrap-text--> <!--rehype:className=wrap-text-->
### 初始化块
```kotlin
class Student(val name: String, val gpa: Double, val semester: String, val estimatedGraduationYear: Int) {
init {
println("$name has ${estimatedGraduationYear - 2020} years left in college.")
}
}
fun main() {
var student = Student("Lucia", 3.95, "Fall", 2022)
// Prints: Lucia has 2 years left in college.
}
```
<!--rehype:className=wrap-text-->
另见 另见
--- ---