//可見性修飾符  函數(shù)關鍵字 方法法名     參數(shù)名 參數(shù)類型          返回值
private       fun      functionName(age: Int, name: String): String {
    return name + age;
}

fun main() {
    //通常調(diào)用方式
    fix("xiaohua", 20)
    //age已經(jīng)給定默認值，此時可以不傳參數(shù)
    fix("xiaohua")
}
//參數(shù)age 給定默認值
fun fix(name: String, age: Int = 18) {
    println(name + age)
}

  println( fix("xiaohua"))

//具名函數(shù)
fun sayHello(): String {
    return "Hello world！"
}
fun main() {
    //具名函數(shù)調(diào)用
    println(sayHello())
}

 val hello: String = "hello"

fun main() {
    //聲明一個匿名函數(shù)，并賦值給變量sayHello
    val sayHello: () -> String = {
        "Hello world!"
    }
    //匿名函數(shù)調(diào)用
    println(sayHello())
}

fun main() {
    //聲明一個匿名函數(shù)，并賦值給變量sayHello
    val sayHello: () -> String = {
        "Hello world!"
    }
    //打印函數(shù)變量
    println(sayHello)
}

fun main() {
    val sayHello: (name: String) -> String = { name ->
        "Hello $name!"
    }
    println(sayHello("HanMei"))
}

fun main() {
    val sayHello: (name: String) -> String = {
        "Hello $it!"
    }
    println(sayHello("HanMei"))
}

fun main() {
    val sayHello: (String, Int) -> String = { name, age ->
        "Hello $name$age"
    }
    println(sayHello("HanMei",18))
}

fun main() {
    val sayHello = {
        "Hello world!"
    }
    println(sayHello())
}

fun main() {
    val sayHello={ name:String ->
        "Hello $name!"
    }
    println(sayHello("HanMei"))
}

fun main() {
    val sayHello = { name: String, age: Int ->
        "Hello $name$age!"
    }
    println(sayHello("HanMei", 18))
}

//定義一個具名函數(shù)，接收一個String參數(shù)和一個函數(shù)參數(shù)happyNewYear
//happyNewYear: (name: String, year: Int) -> String 這個就是匿名函數(shù)的定義
fun sayhello(name: String, happyNewYear: (name: String, year: Int) -> String) {
    val year = 2022
    //在具名函數(shù)中調(diào)用傳遞進來的匿名函數(shù)
    println(happyNewYear(name,year))
}

fun main() {
    //定義一個匿名函數(shù)
    val happyNewYear = { name: String, year: Int ->
        "${name},happy ${year}!"
    }
    //調(diào)用具名函數(shù)，并把匿名函數(shù)當作參數(shù)傳遞
    sayhello("HanMei", happyNewYear)
}

fun main() {
    sayhello("HanMei", happyNewYear = { name: String, year: Int ->
        "${name},happy ${year}!"
    })
}

fun main() {
    sayhello("HanMei") { name: String, year: Int ->
        "${name},happy ${year}!"
    }
}

  val word = "HappyNewYear"
  var count = word.count()

    count =  word.count({ letter ->
        letter == 'a'
    })

count =  word.count { letter -> letter == 'a' }

count = word.count { it == 'a' }

fun happyNewYear(name: String, year: Int): String {
    return "$name happy $year"
}
fun sayhello(name: String, happyNewYear: (name: String, year: Int) -> String) {
    val year = 2022
    println(happyNewYear(name, year))
}

fun main() {
    //::happyNewYear這個就是函數(shù)的引用，
    sayhello("HanMei",::happyNewYear)
}

fun sayhello(): (String) -> String {
    return {
        val year = 2022
        "$it happy $year"
    }
}

fun main() {
    //調(diào)用sayhello得到這個匿名函數(shù)，并賦值給變量happyNewYear
    val happyNewYear = sayhello();
    //happyNewYear就是一個匿名函數(shù)，可以直接傳參調(diào)用
    println(happyNewYear("HanMei"))
}

fun sayhello(): (String) -> String {
    val year = 2022
    return {
        "$it happy $year"
    }
}