add Go implementation of monte carlo (#165)

* add Go implementation of monte carlo

* Add Go heading before import in monte carlo

* Update monteCarlo.go

* Update monte_carlo.md

Author: chin123

chapters/monte_carlo/code/go/monteCarlo.go

@@ -0,0 +1,37 @@
+// Submitted by Chinmaya Mahesh (chin123)
+
+package main
+
+import (
+	"fmt"
+	"math"
+	"math/rand"
+	"time"
+)
+
+func inCircle(x, y float64) bool {
+	return x*x+y*y < 1.0 // the radius of an unit circle is 1.0
+}
+
+func monteCarlo(samples int) {
+	count := 0
+	s := rand.NewSource(time.Now().UnixNano())
+	r := rand.New(s)
+
+	for i := 0; i < samples; i++ {
+		x, y := r.Float64(), r.Float64()
+
+		if inCircle(x, y) {
+			count += 1
+		}
+	}
+	
+	estimate := 4.0 * float64(count) / float64(samples)
+
+	fmt.Println("The estimate of pi is", estimate)
+	fmt.Printf("Which has an error of %f%%\n", 100*math.Abs(math.Pi-estimate)/math.Pi)
+}
+
+func main() {
+	monteCarlo(10000000)
+}

chapters/monte_carlo/monte_carlo.md

@@ -47,6 +47,8 @@ each point is tested to see whether it's in the circle or not:
 [import:7-9, lang:"rust"](code/rust/monte_carlo.rs)
 {% sample lang="d" %}
 [import:2-5, lang:"d"](code/rust/monte_carlo.d)
+{% sample lang="go" %}
+[import:12-14, lang:"go"](code/go/monteCarlo.go)
 {% endmethod %}
 
 If it's in the circle, we increase an internal count by one, and in the end,
@@ -93,6 +95,9 @@ Feel free to submit your version via pull request, and thanks for reading!
 ### D
 {%sample lang="d" %}
 [import, lang:"d"](code/d/monte_carlo.d)
+### Go
+{%sample lang="go" %}
+[import, lang:"go"](code/go/monteCarlo.go)
 {% endmethod %}