scala基础&函数

Posted 2021-01-04 yangjiming

基础的scala语法和函数

package com.yjm.scala

object Person {
  def main(args: Array[String]): Unit = {

  }
  var age = 20
  if (age > 20) {
    println("可以观看欧美")
  } else if (age > 18) {
    println("可以看国产")
  } else {
    println("禁止观看")
  }

  var count = 1
  while (count < 102) {
    println("第" + count + "次迟到")
    count += 1
  }

  do {
    count -= 1
    println("第" + count + "次迟到")
  } while (count > 1)

  println(1 to 10)
  println(1.to(10, 2)) //步长为2

  println(1 until 10)
  println(1.until(10, 2)) //步长为2

  //统计 1-100的和
  var sum = 0
  for (elem <- 1 to 100) {
    sum += elem
  }
  println(sum)

  //返回一个集合
  val oss = for (i <- 1 to 100; if i % 2 == 0) yield i
  for (elem <- oss) {
    println(elem)
  }

  /**
   * 函数
   */
  def add(num1:Int,num2:Int):Int={
    num1+num2
  }
  println(add(1,2))
  
  /**
   * 递归函数
   */
  def fun(num:Int):Int={
    if(num==1){
      num
    }else{
      num*fun(num-1)
    }
  }
  println(fun(10))
  
  /**
   * 默认参数的函数
   */
  def fun3(n1:Int=10,n2:Int)={
    n1+n2
  }
  println(fun3(n1=9,n2=100))
  /**
   * 乘法表
   */
  for(i <- 1 to 9 ;j <- 1 to i){
    print(i+"*"+j+"="+ j*i+"	" )
    if(j==i){
      println()
    }
  }
}