move out c/cpp/py

cl/_testgo/tpindex/in.go

@@ -0,0 +1,18 @@
+package main
+
+// The index function returns the index of the first occurrence of v in s,
+// or -1 if not present.
+func index[E comparable](s []E, v E) int {
+	for i, vs := range s {
+		if v == vs {
+			return i
+		}
+	}
+	return -1
+}
+
+func main() {
+	s := []int{1, 3, 5, 2, 4}
+	println(index(s, 3))
+	println(index(s, 6))
+}