ch05 exercises

exercises/ch05/ex5_4.lua

@@ -0,0 +1,30 @@
+local function polynomial(coefs, x)
+    local sum = 0
+    for i = 1, #coefs do
+        sum = sum + coefs[i] * x^i
+    end
+
+    return sum
+end
+
+local function table_str(t)
+    local str = "{ "
+    for _, v in pairs(t) do
+        str = str + v + ", "
+    end
+
+    str = str + "}"
+end
+
+local function test(coefs, x, should_be)
+    local res = polynomial(coefs, x)
+    if res ~= should_be then
+        print(
+            ("Test failed. Should have been %f, was %f. coefs: %s, x: %f"):format(should_be, res, table_str(coefs), x)
+        )
+    else
+        print("Test passed.")
+    end
+end
+
+test({1, 2, 3}, 2, 1 * 2^1 + 2 * 2^2 + 3 * 2^3)