Functional Programming Principles in Scala. Recfun. Exercise 1: Pascal’s Triangle Exercise 2: Parentheses Balancing Exercise 3: Counting Change

Main.scala

package recfun
import common._

object Main {
  def main(args: Array[String]) {
    println("Pascal's Triangle")
    for (row <- 0 to 10) {
      for (col <- 0 to row)
        print(pascal(col, row) + " ")
      println()
    }
  }

  /**
   * Exercise 1
   */
  def pascal(c: Int, r: Int): Int = (c,r) match {
    case (0,r) => 1
    case (c,r) if (c==r) => 1
    case (c,r) => pascal(c,r-1) + pascal(c-1,r-1)    
  }
  
  //println(pascal(1,10))
  
  /**
   * Exercise 2
   */
  def balance(chars: List[Char]): Boolean = {
    def bal(chars: List[Char],c:List[Char]):Boolean={
      if(chars.isEmpty && c.isEmpty) true
      else if(chars.isEmpty && !(c.isEmpty)) false
      else {
        chars.head match {
          case '(' => bal(chars.tail,'('::c)
          case ')' if(c.isEmpty) => false
          case ')' if(c.head=='(') => bal(chars.tail,c.tail)
          case _ => bal(chars.tail,c) 
        }
      }
    }
    bal(chars,List())
  }
  
 
  

  /**
   * Exercise 3
   */
  def countChange(money: Int, coins: List[Int]): Int = { 
     if(money==0) 0 else
     coins match {
        case Nil if(money>0) => 0
        case m :: ms if(money>m) => countChange(money-m, coins) + countChange(money,ms)
        case m :: ms if(money==m) => 1 + countChange(money,ms) 
        case m :: ms if(money<m) => countChange(money, ms)
      }
  }
}

hi,
can you please share the recfun.zip ?
it's unavailable from the page right now :(
(the one original zip file that you downloaded from server)