starting go by example

5-go-by-example/4-constants.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"fmt"
+	"math"
+)
+
+// const declares a constant value.
+const s string = "constant"
+
+func main() {
+	fmt.Println(s)
+
+	// can appear anywhere a var statement can
+	const n = 500000000
+
+	// expressions perform arithmetic with arbitrary precision
+	const d = 3e20 / n
+	fmt.Println(d)
+
+	// numeric constants have no type until it’s given one
+	fmt.Println(int64(d))
+
+	// numbers can be given a type by using it in a context that requires one
+	fmt.Println(math.Sin(n))
+}