https://ocw.cs.pub.ro/ppcarte/ 2026-06-10T05:59:36+03:00 https://ocw.cs.pub.ro/ppcarte/ https://ocw.cs.pub.ro/ppcarte/lib/tpl/bootstrap3/images/favicon.ico text/html 2023-03-15T14:31:40+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:curs02&rev=1678883500&do=diff Curs 02. Functii de ordin superior import scala.annotation.tailrec val x = 0 "Matei" val b = if (x > 0) 1 else 0 var y = 0 def f(x: Int): Int = { var y = x y = y + 1 y } // definitia unei functii // care se numeste f // si are un parametru de tip int, care se numeste x // f intoarce un Int // expresia la care se evalueaza f este x + 1 f(1) def myAddition(x: Int, y: Int): Int = x + y myAddition(2,3) def inRange(start: Int, stop: Int, x: Int):Boolean = x >= start && x <= stop def… text/html 2023-03-15T14:32:44+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:curs03&rev=1678883564&do=diff Curs 03. Functii de ordin superior /* Suppose we want to compute the sum of all integers from a range: */ def sumAll(start: Int, stop: Int): Int = { def loop (i: Int, crtSum: Int): Int = if (i > stop) crtSum else loop(i+1,crtSum+i) loop(start,0) } //... as well as the sum x*x of all elements def sumSquares(start: Int, stop: Int): Int = { def loop (i: Int, crtSum: Int): Int = if (i > stop) crtSum else loop(i+1,crtSum+i*i) loop(start,0) } // we can see that the code is … text/html 2023-03-15T14:33:45+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:curs04&rev=1678883625&do=diff Curs 04. Tipuri de date functionale in Scala /* class Point (val x: Int, val y: Int) { def higher(p: Point): Boolean = p.x > this.x // string interpolation override def toString: String = s"(${x},${y})" } new Point(1,2) val p = new Point(1,2) p.x new Point(1,2) == new Point(1,2) */ trait Nat // pt moment, acelasi lucru cu interface case object Zero extends Nat case class Succ(next: Nat) extends Nat Succ(Succ(Succ(Zero))) Succ(Zero) == Succ(Zero) def add(n: Nat, m: Nat): Nat = … text/html 2023-03-15T14:35:20+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:curs05&rev=1678883720&do=diff Curs 5. Liste in Scala // 1 + 2 * 3 trait Expr { def eval(): Int } case class Atom(x: Int) extends Expr { override def eval(): Int = x } case class Add(e1: Expr, e2: Expr) extends Expr { override def eval(): Int = e1.eval() + e2.eval() } case class Mult(e1: Expr, e2: Expr) extends Expr{ override def eval(): Int = e1.eval() * e2.eval() } Add(Atom(1),Mult(Atom(2),Atom(3))).eval() /* - calculeaza valoarea unei expresii - group: e1 * e2 + e1 * e3 = e1 * (e2 + e3) */ def gr… text/html 2023-03-22T18:19:39+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:curs06&rev=1679501979&do=diff Curs 6. Aplicatii cu liste /* Avem un sir, care contine numere si whitespace. "12 4 560 3" Vrem sa realizam un split dupa whitespace al acestui sir: "12", "4", "560", "3" */ type Sir = List[Char] /* Haide sa parsam un CSV. a,b,c d,e,f g,h,i */ val csvContents: Sir = """a,b,c |d,e,f |g,h,i |""".stripMargin.toList type Table = List[List[Sir]] //split('\n')(csvContents) //split('\n')(csvContents) // .map(split(',')) def readCSV(content: Sir): Table = { def split(… text/html 2023-03-28T14:06:18+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:curs07&rev=1680001578&do=diff Curs 07. For expressions si companion objects /* Ce facem azi? - diverse */ // Ranges 1.to(10) val f: (Int,Int) => Range = (start,stop) => start.to(stop) 1.to(10) // nu neaparat natural 1 to 10 // acelasi lucru /* mai general: <object>.<method>(<p1>, ... <pn>) <object> <method> <p1> <p2> .... <pn> */ 1 until 10 1 to 10 by 2 trait Nat { def +(other: Nat): Nat def -(other: Nat): Nat } case object Zero extends Nat { override def + (other: Nat): Nat = other override def - (oth… text/html 2023-03-29T16:00:59+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:curs08&rev=1680094859&do=diff Curs 08. Covarianta tipurilor trait Nat { def +(n: Nat): Nat def -(n: Nat): Nat // difference over naturals, not integers } case object Zero extends Nat { override def + (n: Nat): Nat = n override def - (n: Nat): Nat = Zero } case class Succ(n: Nat) extends Nat { override def + (m: Nat): Nat = Succ(n + m) override def - (m: Nat): Nat = m match { case Zero => Succ(n) case Succ(mp) => n - mp } } /* Vreau sa iau o lista de intregi (Int) si sa o transform intr… text/html 2023-03-01T11:23:33+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:ide&rev=1677662613&do=diff Scala setup Installation Scala can be downloaded and installed on either a Windows or NIX platform (e.g. Linux, OS-X) here. For this lecture you must install Scala 3, and we recommend installing it using Coursier (see the previous link) IDE One of the most widely used IDE (Integrated Development Environment) for Scala is: text/html 2023-03-01T11:21:03+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:l00&rev=1677662463&do=diff Scala setup Installation Scala can be downloaded and installed on either a Windows or NIX platform (e.g. Linux, OS-X) here. For this lecture you must install Scala 3, and we recommend installing it using Coursier (see the previous link) IDE One of the most widely used IDE (Integrated Development Environment) for Scala is: text/html 2023-03-15T18:51:57+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:l01&rev=1678899117&do=diff Lab 1. Introduction to Scala Objectives: * get yourself familiar with Scala syntax basics * practice writing tail-recursive functions as an alternative to imperative loops * keep your code clean and well-structured. Create a new Scala worksheet to write your solutions $ n$$ 1 + 2^2 + 3^2 + \ldots + (n-1)^2 + n^2$$ x$$ x_0, x_1, \ldots, x_n$$ (\ldots((x - x_0) - x_1) - \ldots x_n)$$ x$$ x_0, x_1, \ldots, x_n$$ x_0 - (x_1 - \ldots - (x_n - x)\ldots)$$ \sqrt{a}$$ x_0 = 1$$ x_{n+1} = \d… text/html 2023-04-02T17:28:24+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:l02&rev=1680445704&do=diff Lab 2. High order functions Objectives: * implement and use higher-order functions. A higher-order function takes other functions as parameter or returns them * implement curry and uncurry functions, and how they should be properly used (review lecture).$ a_1, a_2, \ldots, a_k$$ f(a_1)\;op\;f(a_2)\;op\;\ldots f(a_k)$$ f(x) = a*x + b$$ \Delta y$$ \Delta x$ text/html 2023-04-02T17:28:48+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:l03&rev=1680445728&do=diff Lab 3. Lists in Scala Objectives: * get familiar with pattern matching lists, as well as common list operations from Scala and how they work * get familiar with common higher-order functions over lists (partition, map, foldRight, foldLeft, filter) text/html 2023-04-02T17:30:42+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:l04&rev=1680445842&do=diff Lab 4. Data types in Scala Objectives: * get familiar with algebraic data types * get familiar with pattern matching and recursion with them 4.1 Natural Numbers Given the following implementation of the natural numbers, solve the next few exercices.$ \displaystyle \left(\begin{array}{ccc} 1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & 9 \\ \end{array}\right)$$ \displaystyle 2 * \left(\begin{array}{ccc} 1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & 9 \\ \end{array}\right) = \left(\begin{array}{ccc} 2 & 4 & 6 \\… text/html 2023-04-05T23:03:19+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:l05&rev=1680724999&do=diff Lab 5. Polymorphism 5.1. Maps Maps are collections of (key, value) pairs. Keys should be unique, and every key is associated with a value. Some of the fundamental operations on maps include: * retrieving / updating the value associated with a key text/html 2023-04-08T07:49:13+03:00 https://ocw.cs.pub.ro/ppcarte/doku.php?id=pp:2023:scala:l06&rev=1680929353&do=diff Lab 6. Scala on steroids 5-Tic-Tac-Toe Tic Tac Toe is usually played on a 3×3 board, marking positions by each player in rounds. Our game is slightly different (usually called 5-in-a-row): * it can be played on a square board of any size larger or equal to 5