articles/golang.md: factorial example

articles/golang.md

@@ -35,3 +35,29 @@ Compiling and running:
 ```
 go run hello.go
 ```
+
+### Factorial
+```go
+package main;
+
+import "fmt"
+
+// functions starting in uppercase are exported
+func Fact(n uint) uint {
+	res := uint(1)
+	for n > 0 { // no while loop in Go
+		res *= n
+		n--
+	}
+	return res
+}
+
+func main() {
+	// Array literal, the `...` is used to infer its size
+	// If you instead left the [] empty it becomes an slice (heap allocated)
+	ns := [...]uint{0, 4, 10, 1, 5, 8}
+	for _, n := range ns {
+		fmt.Printf("Fact(%d) = %d\n", n, Fact(n))
+	}
+}
+```