lean into examples

examples/random-numbers/random-numbers.go

@@ -0,0 +1,37 @@
+package main
+
+// The `math/rand` package provides psuedo-random
+// numbers.
+import "math/rand"
+import "fmt"
+
+func main() {
+    // For example, `rand.Intn` returns a random `int` n,
+    // `0 <= n < 100`.
+    fmt.Print(rand.Intn(100), ",")
+    fmt.Print(rand.Intn(100))
+    fmt.Println()
+
+    // `rand.Float64` returns a `float64` `f`,
+    // `0.0 <= f < 1.0`.
+    fmt.Println(rand.Float64())
+
+    // To make the psuedo-random generator deterministic,
+    // give it a well-known seed.
+    s1 := rand.NewSource(42)
+    r1 := rand.New(s1)
+
+    // Call the resulting `rand.Source` just like the
+    // functions on the `rand` package.
+    fmt.Print(r1.Intn(100), ",")
+    fmt.Print(r1.Intn(100))
+    fmt.Println()
+
+    // If you seed a source with the same number, it
+    // produces the same sequence of random numbers.
+    s2 := rand.NewSource(42)
+    r2 := rand.New(s2)
+    fmt.Print(r2.Intn(100), ",")
+    fmt.Print(r2.Intn(100))
+    fmt.Println()
+}

examples/random-numbers/random-numbers.sh

@@ -0,0 +1,5 @@
+$ go run random-numbers.go
+81,87
+0.6645600532184904
+5,87
+5,87