add: slice adv. ops. exercises

16-slices/exercises/23-limit-the-backing-array-sharing/solution/api/api.go

@@ -0,0 +1,24 @@
+package api
+
+var temps = []int{5, 10, 3, 25, 45, 80, 90}
+
+// Read returns a range of temperature readings beginning from
+// the `start` until to the `stop`.
+func Read(start, stop int) []int {
+	// Uses a full slice expression to control the length of the
+	// backing array (or the capacity of the returned slice).
+	//
+	// So the next append allocates a new backing array, which
+	// in turn doesn't overwrite the temps slice's backing array.
+	//                           ^^
+	//                           ||
+	//                          /  \
+	//                         |    |
+	portion := temps[start:stop:stop]
+	return portion
+}
+
+// All returns all the temperature readings
+func All() []int {
+	return temps
+}