练习题Scala

import scala.collection.mutable.ListBuffer

//1

case class Book(id: String, name: String, author: String, price: Double, quantity: Int)

 

object Test1 {

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

//2

var bookList =ListBuffer[Book]()

//3

bookList +=Book("001","book1","author1",12,3)

bookList +=Book("002","book2","author2",14,6)

bookList +=Book("003","book3","author3",17,5)

//4

val book1 =Book("005","book5","author5",18,20)

val rs=bookList.find(_.id==book1.id)

if(rs.isEmpty){

println("没有")

bookList +=book1

}else{

println("有")

val s=rs.get

s.quantity+=book1.quantity

}

//5

var name="book5"

val rs1=bookList.find(_.name == name)

if(rs1.isEmpty)

println(s"《$name》 不存在")

else

println(s"《$name》 存在")

//6.

name="book1"

val rs2 = bookList.find(_.name==name)

if(rs2.isEmpty)

println(s"《$name》 不存在，删除失败")

else {

println(s"《$name》 存在，删除成功")

bookList -=rs2.get

}

//7.

val id="002"

val rs3 =bookList.find(_.id == id)

if(rs3.isEmpty)

println(s"id: $id 不存在，删除失败")

else {

println(s"id: $id 存在，删除成功")

bookList-=rs3.get

}

//8.

val orderList=bookList.sortWith((a,b)=>a.price >b.price)

//9.

orderList.foreach(el =>{

println(s"${el.name},${el.author},${el.price},${el.quantity}")

})

//10

var sum:Double=0;

bookList.foreach((el=> {

sum +=(el.quantity*el.price)

}))

println(s"总的金额是：${sum}")

 

}

 

}