lean into examples

examples/functions/functions.go

@@ -0,0 +1,34 @@
+// Funcations are critical in Go as in any other language.
+// We'll look at some basic examples first.
+
+package main
+
+import "fmt"
+
+// The syntax is `func name(args) returns { body }`. Note
+// the the types of arguments come after their name.
+// In this case we're taking a slice of floats and
+// returning a single float value.
+func avg(vals []float64) float64 {
+    total := 0.0
+    for _, val := range vals {
+        total += val
+    }
+    // Go requires an expliciti return, i.e. it won't
+    // automatically return the value of the last
+    // expression.
+    return total / float64(len(vals))
+}
+
+func main() {
+    input := []float64{98, 93, 77, 82, 83}
+    fmt.Println(input)
+    // Call a function just as you'd expect, with
+    // `name(args)`.
+    output := avg(input)
+    fmt.Println(output)
+}
+
+// There are several other features to Go functions,
+// including multiple return values and varargs, which
+// we'll look at next.