diff -r 2345ba5b4264 -r 197babb05539 Fahad/Scala/Chapter5.sc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Fahad/Scala/Chapter5.sc	Sat Oct 25 17:28:56 2014 +0100
@@ -0,0 +1,55 @@
+package greeter
+
+object Chapter5 {
+  println("Welcome to the Scala worksheet")       //> Welcome to the Scala worksheet
+
+  /////////////////////////////////////////////////////////////////////////////
+  //   CHAPTER 5: FIRST-CLASS FUNCTIONS
+
+  /*
+  // Write a function to sumall integers between two given numbers a and b
+  def sumInts(a: Int, b: Int): Int =
+    if (a > b) 0 else a + sumInts(a + 1, b)
+
+  sumInts(1, 5)
+
+  //Write a function to sum the squares of all integers between two given numbers a and b
+  def square(x: Int): Int = x * x
+  def sumSquares(a: Int, b: Int): Int =
+    if (a > b) 0 else square(a) + sumSquares(a + 1, b)
+
+  square(5)
+
+  //Write a function to sum the powers 2n of all integers n between two given numbers a and b:
+  def powerOfTwo(x: Int): Int = if (x == 0) 1 else 2 * powerOfTwo(x - 1)
+  def sumPowersOfTwo(a: Int, b: Int): Int =
+    if (a > b) 0 else powerOfTwo(a) + sumPowersOfTwo(a + 1, b)
+
+  sumPowersOfTwo(2, 4)
+  */
+
+  def sum(f: Int => Int, a: Int, b: Int): Int =
+    if (a > b) 0 else f(a) + sum(f, a + 1, b)     //> sum: (f: Int => Int, a: Int, b: Int)Int
+
+  //def sumInts(a: Int, b: Int): Int = sum(id, a, b)
+  //def sumInts(a: Int, b: Int): Int = sum((x: Int) => x, a, b)
+  def sumInts(a: Int, b: Int): Int = sum(x => x, a, b)
+                                                  //> sumInts: (a: Int, b: Int)Int
+  //def sumSquares(a: Int, b: Int): Int = sum(square, a, b)
+  //def sumSquares(a: Int, b: Int): Int = sum((x: Int) => x * x, a, b)
+  def sumSquares(a: Int, b: Int): Int = sum(x => x * x, a, b)
+                                                  //> sumSquares: (a: Int, b: Int)Int
+  def sumPowersOfTwo(a: Int, b: Int): Int = sum(powerOfTwo, a, b)
+                                                  //> sumPowersOfTwo: (a: Int, b: Int)Int
+  
+  def id(x: Int): Int = x                         //> id: (x: Int)Int
+	def square(x: Int): Int = x * x           //> square: (x: Int)Int
+	def powerOfTwo(x: Int): Int = if (x == 0) 1 else 2 * powerOfTwo(x - 1)
+                                                  //> powerOfTwo: (x: Int)Int
+                                                  
+  // 5.2: Currying
+  
+  
+  
+  
+}
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