pep-material: comparison progs/lecture1.scala

equal deleted inserted replaced

-:6253f4681451
+:a7afc2540a88
 // Lecture 1
 //===========
-// Assignments (values)
+// Value assignments
 // (variable names should be lower case)
 //======================================
 val x = 42
 val y = 3 + 4
 //==================
 println("test")
-val tst = "This is a " + "test"
+val tst = "This is a " ++ "test\n"
 println(tst)
 val lst = List(1,2,3,1)
 println(lst.toString)
 /* boolean operators
 ==     equals
 !      not
 && ||  and, or
 */
 def fact2(n: BigInt): BigInt =
 if (n == 0) 1 else n * fact2(n - 1)
 fact2(150)
 def fib(n: Int): Int =
 if (n == 0) 1 else
-if (n == 1) 1 else fib(n - 1) + f(n - 2)
+if (n == 1) 1 else fib(n - 1) + fib(n - 2)
-//a recursive function
+//gcd - Euclid's algorithm
-def gcd(x: Int, y: Int): Int = 2 //???
+def gcd(a: Int, b: Int): Int =
+if (b == 0) a else gcd(b, a % b)
+gcd(48, 18)
 // String Interpolations
 //=======================
+val n = 3
+println("The square of " + n + " is " + square(n) + ".")
+println(s"The square of ${n} is ${square(n)}.")
+def gcd_db(a: Int, b: Int): Int = {
+println(s"Function called with ${a} and ${b}.")
+if (b == 0) a else gcd_db(b, a % b)
+}
+gcd_db(48, 18)
 // Assert/Testing
 //================
-// For-Maps (not For-Loops)
+// For-Comprehensions (not For-Loops)
-//==========================
+//====================================
 for (n <- (1 to 10).toList) yield square(n)
 for (n <- (1 to 10).toList;
 m <- (1 to 10).toList) yield m * n
-val mtable = for (n <- (1 to 10).toList;
+val mult_table =
-m <- (1 to 10).toList) yield m * n
+for (n <- (1 to 10).toList;
+m <- (1 to 10).toList) yield m * n
-mtable.sliding(10,10).mkString("\n")
+mult_table.sliding(10,10).mkString("\n")
+// with patterns
+for ((m, n) <- List((1, 4), (2, 3), (3, 2), (4, 1))) yield m + n
+for (p <- List((1, 4), (2, 3), (3, 2), (4, 1))) yield p._1 + p._2
 // Webpages
 //==========

changeset 26	a7afc2540a88
parent 25	6253f4681451
child 32	45557ad18ea6