while语句习题和for语句习题

while

习题 问题1+1/2+1/3+1/4....+1/19

object w12 {
  def main(args: Array[String]): Unit = {
    //1.问题1+1/2+1/3+1/4....+1/19
    var i =1
    var sum =0.0
    while(i<=19){

      sum =sum +1.0/i
      i=i+1

    }
    println(sum)
  }


}

习题 问题:1-1/2+1/3....+1/19

object w13 {
  def main(args: Array[String]): Unit = {
//问题2:1-1/2+1/3....+1/19
    var i = 1
    var sum = 0.0
    while (i <= 19) {

      if (i % 2 == 1) {
        sum = sum + 1.0 / i
      } else {
        sum = sum - 1.0 / i
      }
      i = i + 1
    }
    println(s"${sum}")
  }
}

习题判断是否为素数

import scala.util.control.Breaks.{break, breakable}

object w14 {
  def main(args: Array[String]): Unit = {
    println(Math.sqrt(97))
    var num =97
    var isprime =true
    var i=2
    breakable{
      while (i<=Math.sqrt(num)){
        if (num%i==0){
          isprime =false
          println(s"${num}能被${i}整除")
          break
        }
        i +=1
      }
    }
    println(i)
    if(isprime){
      println(s"${num}是素数")
    }else{
      println(s"${num}不是素数")
    }
  }
}

习题 //求它第10年结束时有多少元

object w15 {
  def main(args: Array[String]): Unit = {
    var i =0
    var money =1.0
    while(i <10){
      money=money*1.1
      i =i +1
      println(s"第${i}年结束时,钱数为${money}")
    }
  }
}

习题 多少年能超过1000

object w16 {
  def main(args: Array[String]): Unit = {
    var i =0
    var money =1.0
    while(money<=1000){
      money=money*1.1
      i =i +1
      println(s"第${i}年结束时,钱数为${money}")
    }
  }
}

for语句

习题

object w17 {
  def main(args: Array[String]): Unit = {
    var sum =0
   for(i<-1 to 10 by 2){
     println(i)
     sum +=i
   }
    println(sum)
  }
}

问题:1-1/2+1/3....+1/19

object w18 {
  def main(args: Array[String]): Unit = {
    var s = 0.0
    for (i <- 1 to 19) {
      if (i % 2 == 1)
        s += 1.0 / i else s -= 1.0 / i

    }
    println(s)
  }

}