added assignment 4 ex 4

src/Assignment4/Ex4_Predicates.sc

@@ -0,0 +1,24 @@
+import scala.annotation.tailrec
+
+@tailrec
+def any[T](p: T => Boolean)(l: List[T]): Boolean = {
+  if (l.isEmpty) false
+  else if (p(l.head)) true
+  else any(p)(l.tail)
+}
+
+@tailrec
+def every[T](p: T => Boolean)(l: List[T]): Boolean = {
+  if (l.isEmpty) true
+  else if (!p(l.head)) false
+  else every(p)(l.tail)
+}
+
+val a = List(1, 2, 3, 4, 5)
+assert(!any((x: Int) => x == 12)(a))
+assert(any((x: Int) => x > 4)(a))
+
+val a = List(1, 2, 3, 4, 5)
+val b = List(2, 4, 6, 8, 10)
+assert(!every((x: Int) => (x % 2) == 0)(a))
+assert(every((x: Int) => (x % 2) == 0)(b))