Initial data commit

Task/Forward-difference/Tcl/forward-difference.tcl

@@ -0,0 +1,23 @@
+proc do_fwd_diff {list} {
+    set previous [lindex $list 0]
+    set new [list]
+    foreach current [lrange $list 1 end] {
+        lappend new [expr {$current - $previous}]
+        set previous $current
+    }
+    return $new
+}
+
+proc fwd_diff {list order} {
+    while {$order >= 1} {
+        set list [do_fwd_diff $list]
+        incr order -1
+    }
+    return $list
+}
+
+set a {90.5 47 58 29 22 32 55 5 55 73.5}
+
+for {set order 0} {$order <= 10} {incr order} {
+    puts [format "%d\t%s" $order [fwd_diff $a $order]]
+}