concurrency/generator: implement generator pattern

concurrency/generators.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"fmt"
+)
+
+//FibonacciClosure implements fibonacci number generation using closure
+func FibonacciClosure() func() int {
+	a, b := 0, 1
+	return func() int {
+		a, b = b, a+b
+		return a
+	}
+}
+
+//FibonacciChan implements fibonacci number generation using channel
+func FibonacciChan(n int) chan int {
+	c := make(chan int)
+
+	go func() {
+		a, b := 0, 1
+		for i := 0; i < n; i++ {
+			c <- b
+			a, b = b, a+b
+		}
+		close(c)
+	}()
+
+	return c
+}
+
+func main() {
+	//closure
+	nextFib := FibonacciClosure()
+	for i := 0; i < 20; i++ {
+		fmt.Println(nextFib())
+	}
+
+	//channel
+	for i := range FibonacciChan(20) {
+		fmt.Println(i)
+	}
+}