--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/templates5/bf.scala	Thu Dec 06 13:52:50 2018 +0000
@@ -0,0 +1,194 @@
+// Part 1 about an Interpreter for the Brainf*** language
+//========================================================
+
+
+// representation of Bf memory 
+
+type Mem = Map[Int, Int]
+
+
+// (1) Write a function that takes a file name as argument and
+// and requests the corresponding file from disk. It returns the
+// content of the file as a String. If the file does not exists,
+// the function should return the empty string.
+
+import io.Source
+import scala.util._
+
+//def load_bff(name: String) : String = ...
+
+
+
+// (2) Complete the functions for safely reading  
+// and writing brainf*** memory. Safely read should
+// Return the value stored in the Map for a given memory
+// pointer, provided it exists; otherwise it Returns 0. The
+// writing function generates a new Map with the
+// same data, except at the given memory pointer the
+// value v is stored.
+
+
+//def sread(mem: Mem, mp: Int) : Int = ...
+
+//def write(mem: Mem, mp: Int, v: Int) : Mem = ...
+
+
+
+// (3) Implement the two jumping instructions in the 
+// brainf*** language. In jumpRight, given a program and 
+// a program counter move the program counter to the right 
+// until after the *matching* ]-command. Similarly, 
+// jumpLeft implements the move to the left to just after
+// the *matching* [-command.
+
+//def jumpRight(prog: String, pc: Int, level: Int) : Int = ...
+
+//def jumpLeft(prog: String, pc: Int, level: Int) : Int = ...
+
+
+// testcases
+//jumpRight("""--[..+>--],>,++""", 3, 0)         // => 10
+//jumpLeft("""--[..+>--],>,++""", 8, 0)          // => 3
+//jumpRight("""--[..[+>]--],>,++""", 3, 0)       // => 12
+//jumpRight("""--[..[[-]+>[.]]--],>,++""", 3, 0) // => 18
+//jumpRight("""--[..[[-]+>[.]]--,>,++""", 3, 0)  // => 22 (outside)
+//jumpLeft("""[******]***""", 7, 0)              // => -1 (outside)
+
+
+
+// (4) Complete the compute function that interprets (runs) a brainf***
+// program: the arguments are a program (represented as a string), a program 
+// counter, a memory counter and a brainf*** memory. It Returns the
+// memory at the stage when the execution of the brainf*** program
+// finishes. The interpretation finishes once the program counter
+// pc is pointing to something outside the program string.
+// If the pc points to a character inside the program, the pc, 
+// memory pointer and memory need to be updated according to 
+// rules of the brainf*** language. Then, recursively, the compute 
+// function continues with the command at the new program
+// counter. 
+//
+// Implement the run function that calls compute with the program
+// counter and memory counter set to 0.
+
+
+//def compute(prog: String, pc: Int, mp: Int, mem: Mem) : Mem = ...
+
+//def run(prog: String, m: Mem = Map()) = ...
+
+
+/*
+
+// some sample bf-programs collected from the Internet
+//=====================================================
+
+
+// first some contrived (small) programs
+
+// clears the 0-cell
+run("[-]", Map(0 -> 100))    // Map will be 0 -> 0
+
+// copies content of the 0-cell to 1-cell
+run("[->+<]", Map(0 -> 10))  // Map will be 0 -> 0, 1 -> 10
+
+
+// copies content of the 0-cell to 2-cell and 4-cell
+run("[>>+>>+<<<<-]", Map(0 -> 42))
+
+
+// prints out numbers 0 to 9
+run("""+++++[->++++++++++<]>--<+++[->>++++++++++<<]>>++<<----------[+>.>.<+<]""")
+
+
+// some more "useful" programs
+
+// hello world program 1
+run("""++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++
+       ..+++.>>.<-.<.+++.------.--------.>>+.>++.""")
+
+// hello world program 2
+run("""++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>+
+      +.<<+++++++++++++++.>.+++.------.--------.>+.>.""")
+
+
+// draws the Sierpinski triangle
+run("""++++++++[>+>++++<<-]>++>>+<[-[>>+<<-]+>>]>+[-<<<[
+      ->[+[-]+>++>>>-<<]<[<]>>++++++[<<+++++>>-]+<<++.[-]<<
+      ]>.>+[>>]>+]""")
+
+run(load_bff("sierpinski.bf"))
+
+
+//fibonacci numbers below 100
+run("""+++++++++++
+      >+>>>>++++++++++++++++++++++++++++++++++++++++++++
+      >++++++++++++++++++++++++++++++++<<<<<<[>[>>>>>>+>
+      +<<<<<<<-]>>>>>>>[<<<<<<<+>>>>>>>-]<[>++++++++++[-
+      <-[>>+>+<<<-]>>>[<<<+>>>-]+<[>[-]<[-]]>[<<[>>>+<<<
+      -]>>[-]]<<]>>>[>>+>+<<<-]>>>[<<<+>>>-]+<[>[-]<[-]]
+      >[<<+>>[-]]<<<<<<<]>>>>>[+++++++++++++++++++++++++
+      +++++++++++++++++++++++.[-]]++++++++++<[->-<]>++++
+      ++++++++++++++++++++++++++++++++++++++++++++.[-]<<
+      <<<<<<<<<<[>>>+>+<<<<-]>>>>[<<<<+>>>>-]<-[>>.>.<<<
+      [-]]<<[>>+>+<<<-]>>>[<<<+>>>-]<<[<+>-]>[<+>-]<<<-]""")
+
+
+//outputs the square numbers up to 10000
+run("""++++[>+++++<-]>[<+++++>-]+<+[
+    >[>+>+<<-]++>>[<<+>>-]>>>[-]++>[-]+
+    >>>+[[-]++++++>>>]<<<[[<++++++++<++>>-]+<.<[>----<-]<]
+    <<[>>>>>[>>>[-]+++++++++<[>-<-]+++++++++>[-[<->-]+[<<<]]<[>+<-]>]<<-]<<-]""")
+
+//collatz numbers (needs a number to be typed in)
+run(""">,[[----------[
+      >>>[>>>>]+[[-]+<[->>>>++>>>>+[>>>>]++[->+<<<<<]]<<<]
+      ++++++[>------<-]>--[>>[->>>>]+>+[<<<<]>-],<]>]>>>++>+>>[
+      <<[>>>>[-]+++++++++<[>-<-]+++++++++>[-[<->-]+[<<<<]]<[>+<-]>]
+      >[>[>>>>]+[[-]<[+[->>>>]>+<]>[<+>[<<<<]]+<<<<]>>>[->>>>]+>+[<<<<]]
+      >[[>+>>[<<<<+>>>>-]>]<<<<[-]>[-<<<<]]>>>>>>>
+      ]>>+[[-]++++++>>>>]<<<<[[<++++++++>-]<.[-]<[-]<[-]<]<,]""")
+
+
+// infinite collatz (never stops)
+run(""">>+>+<[[->>[>>]>>>[>>]+[<<]<<<[<<]>[>[>>]>>+>[>>]<+<[<<]<<<[<
+      <]>-]>[>>]>>[<<<<[<<]>+>[>>]>>-]<<<<[<<]+>>]<<[+++++[>+++++++
+      +<-]>.<++++++[>--------<-]+<<]>>[>>]+[>>>>[<<+>+>-]<-[>+<-]+<
+      [<<->>-[<<+>>[-]]]>>>[<<<+<<+>>>>>-]<<<[>>>+<<<-]<<[[-]>+>>->
+      [<+<[<<+>>-]<[>+<-]<[>+<-]>>>>-]<[>+<-]+<[->[>>]<<[->[<+++>-[
+      <+++>-[<+++>-[<[-]++>>[-]+>+<<-[<+++>-[<+++>-[<[-]+>>>+<<-[<+
+      ++>-[<+++>-]]]]]]]]]<[>+<-]+<<]>>>+<[->[<+>-[<+>-[<+>-[<+>-[<
+      +>-[<+>-[<+>-[<+>-[<+>-[<[-]>>[-]+>+<<-[<+>-]]]]]]]]]]]<[>+<-
+      ]+>>]<<[<<]>]<[->>[->+>]<[-[<+>-[<->>+<-[<+>-[<->>+<-[<+>-[<-
+      >>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>
+      -[<->>+<-[<+>-[<->>+<-[<+>-]]]]]]]]]]]]]]]]]]]>[<+>-]<+<[<+++
+      +++++++>-]<]>>[<+>->>]<<[>+>+<<-]>[<+>-]+>[<->[-]]<[-<<-]<<[<
+      <]]++++++[>+++++++<-]>++.------------.[-]>[>>]<<[+++++[>+++++
+      +++<-]>.<++++++[>--------<-]+<<]+<]>[<+>-]<]>>>[>>]<<[>[-]<-<
+      <]++++++++++.[-]<<<[<<]>>>+<[->[<+>-[<+>-[<+>-[<+>-[<+>-[<+>-
+      [<+>-[<+>-[<+>-[<[-]>>[-]+>+<<-]]]]]]]]]]<[>+<-]+>>]<<[<<]>>]""")
+
+
+
+// a Mandelbrot set generator in brainf*** written by Erik Bosman
+// (http://esoteric.sange.fi/brainfuck/utils/mandelbrot/)
+
+run(load_bff("mandelbrot.bf"))
+
+
+// a benchmark program (counts down from 'Z' to 'A')
+val b1 = """>++[<+++++++++++++>-]<[[>+>+<<-]>[<+>-]++++++++
+            [>++++++++<-]>.[-]<<>++++++++++[>++++++++++[>++
+            ++++++++[>++++++++++[>++++++++++[>++++++++++[>+
+            +++++++++[-]<-]<-]<-]<-]<-]<-]<-]++++++++++."""
+
+
+def time_needed[T](n: Int, code: => T) = {
+  val start = System.nanoTime()
+  for (i <- 0 until n) code
+  val end = System.nanoTime()
+  (end - start)/1.0e9
+}
+
+time_needed(1, run(b1))
+*/
+