Data commit

Task/Middle-three-digits/Tcl/middle-three-digits-1.tcl

@@ -0,0 +1,14 @@
+proc middleThree n {
+    if {$n < 0} {
+	set n [expr {-$n}]
+    }
+    set idx [expr {[string length $n] - 2}]
+    if {$idx % 2 == 0} {
+	error "no middle three digits: input is of even length"
+    }
+    if {$idx < 1} {
+	error "no middle three digits: insufficient digits"
+    }
+    set idx [expr {$idx / 2}]
+    string range $n $idx [expr {$idx+2}]
+}

Task/Middle-three-digits/Tcl/middle-three-digits-2.tcl

@@ -0,0 +1,12 @@
+foreach n {
+    123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345
+    1 2 -1 -10 2002 -2002 0
+} {
+    if {[catch {
+	set mid [middleThree $n]
+    } msg]} then {
+	puts "error for ${n}: $msg"
+    } else {
+	puts "found for ${n}: $mid"
+    }
+}