Scala自定义while循环

Posted 2022-01-30 辉常努腻

你用过自定义的while循环码？

• 真厉害了Scala

package com.li.chapter05

import java.util.concurrent.locks.Condition

object Test12_MyWhile 
  def main(args: Array[String]): Unit = 
    var n = 10

    // 1. 常规的while循环
    while (n >= 1)
      println(n)
      n -= 1
    

    // 2. 用闭包实现一个函数，将代码块作为参数传入，递归调用
    def myWhile(condition: =>Boolean): (=>Unit)=>Unit = 
      // 内层函数需要递归调用，参数就是循环体
      def doLoop(op: =>Unit): Unit = 
        if (condition)
          op
          myWhile(condition)(op)
        
      
      doLoop _
    

    println("=================")
    n = 10
    myWhile(n >= 1)
      println(n)
      n -= 1
    

    // 3. 用匿名函数实现
    def myWhile2(condition: =>Boolean): (=>Unit)=>Unit = 
      // 内层函数需要递归调用，参数就是循环体
      op => 
        if (condition)
          op
          myWhile2(condition)(op)
        
      
    
    println("=================")
    n = 10
    myWhile2(n >= 1)
      println(n)
      n -= 1
    

    // 3. 用柯里化实现
    def myWhile3(condition: =>Boolean)(op: =>Unit): Unit = 
      if (condition)
        op
        myWhile3(condition)(op)
      
    

    println("=================")
    n = 10
    myWhile3(n >= 1)(
      println(n)
      n -= 1
    )

    
    //使用双参数代码块实现自定义while    
    def myWhile4(condition: =>Boolean,op: =>Unit): Unit =
      if (condition)
        op
        myWhile4(condition,op)
      
    

    println("=================")
    n = 10
    myWhile4(n >= 1,
      println(n)
      n -= 1
    )