adding recursion examples

Author: symonk

main.go

@@ -14,6 +14,7 @@ import (
 	"github.com/symonk/learning-golang/ifelse"
 	"github.com/symonk/learning-golang/maps"
 	"github.com/symonk/learning-golang/ranges"
+	"github.com/symonk/learning-golang/recursion"
 	"github.com/symonk/learning-golang/slices"
 	"github.com/symonk/learning-golang/switches"
 	"github.com/symonk/learning-golang/tickers"
@@ -42,6 +43,7 @@ var (
 		functions.Run,
 		variables.Run,
 		closures.Run,
+		recursion.Run,
 	}
 )
 

recursion/main.go

@@ -1,5 +1,31 @@
 package recursion
 
+import "fmt"
+
+/* Go supports `recursive function`, a function that internally calls itself.*/
 func Run() {
+	fmt.Println(factorial(3)) // 6
+	fibonacci := recursiveClosureFibonacci()
+	fmt.Println(fibonacci(10)) // 55
+}
+
+func factorial(n int) int {
+	// Define the exit criteria to avoid infinite recursion.
+	if n == 1 {
+		return n
+	}
+	return n * factorial(n-1)
+}
+
+func recursiveClosureFibonacci() func(int) int {
+	// Closures can also be recursive
 
+	var fib func(n int) int
+	fib = func(n int) int {
+		if n < 2 {
+			return n
+		}
+		return fib(n-1) + fib(n-2)
+	}
+	return fib
 }