Add the tiger source code bundle from the book site

Signed-off-by: jmug <u.g.a.mariano@gmail.com>

tiger/testcases/queens.tig

@@ -0,0 +1,34 @@
+/* A program to solve the 8-queens problem */
+
+let
+    var N := 8
+
+    type intArray = array of int
+
+    var row := intArray [ N ] of 0
+    var col := intArray [ N ] of 0
+    var diag1 := intArray [N+N-1] of 0
+    var diag2 := intArray [N+N-1] of 0
+
+    function printboard() =
+       (for i := 0 to N-1
+	 do (for j := 0 to N-1 
+	      do print(if col[i]=j then " O" else " .");
+	     print("\n"));
+         print("\n"))
+
+    function try(c:int) = 
+( /*  for i:= 0 to c do print("."); print("\n"); flush();*/
+     if c=N
+     then printboard()
+     else for r := 0 to N-1
+	   do if row[r]=0 & diag1[r+c]=0 & diag2[r+7-c]=0
+	           then (row[r]:=1; diag1[r+c]:=1; diag2[r+7-c]:=1;
+		         col[c]:=r;
+	                 try(c+1);
+			 row[r]:=0; diag1[r+c]:=0; diag2[r+7-c]:=0)
+
+)
+ in try(0)
+end
+