First commit

exercises/ch04/ex4_5.lua

@@ -0,0 +1,7 @@
+local function remove(str, start, length)
+    local start_part = str:sub(1, start - 1)
+    local end_part = str:sub(start + length, -1)
+    return start_part .. end_part
+end
+
+print(remove("hello world", 7, 4))