diff --git a/circle/circle.go b/circle/circle.go
new file mode 100644
index 0000000..e028d16
--- /dev/null
+++ b/circle/circle.go
@@ -0,0 +1,28 @@
+package circle
+
+import (
+	"fmt"
+)
+
+type Circle interface {
+	Area()
+	Perimeter()
+}
+
+type circ struct {
+	radius int
+}
+
+func NewCircle(r int) Circle {
+	return &circ{
+		radius: r,
+	}
+}
+
+func (c *circ) Area() {
+	fmt.Println("Area of Circle : ", (22/7)*c.radius*c.radius)
+}
+
+func (c *circ) Perimeter() {
+	fmt.Println("Perimeter of Circle : ", 2*(22/7)*c.radius)
+}
diff --git a/cmd/interface/main.go b/cmd/interface/main.go
new file mode 100644
index 0000000..84c91f8
--- /dev/null
+++ b/cmd/interface/main.go
@@ -0,0 +1,15 @@
+package main
+
+import (
+	"github.com/utkarsh-josh/interface/circle"
+	"github.com/utkarsh-josh/interface/rectangle"
+)
+
+func main() {
+	rect := rectangle.NewRectangle(5, 10)
+	circ := circle.NewCircle(14)
+	rect.Area()
+	rect.Perimeter()
+	circ.Area()
+	circ.Perimeter()
+}
diff --git a/cmd/switch/main.go b/cmd/switch/main.go
new file mode 100644
index 0000000..6a13540
--- /dev/null
+++ b/cmd/switch/main.go
@@ -0,0 +1,30 @@
+package main
+
+import (
+	"fmt"
+)
+
+func testDataType(variable interface{}) {
+	switch variable.(type) {
+	case string:
+		fmt.Println("It is a string : ", variable.(string))
+	case int:
+		fmt.Println("It is an integer : ", variable.(int))
+	case float64:
+		fmt.Println("It is a float : ", variable.(float64))
+	default:
+		fmt.Println("Data type not present")
+	}
+}
+
+func main() {
+	var variable interface{}
+	variable = "Utkarsh"
+	testDataType(variable)
+	variable = 10
+	testDataType(variable)
+	variable = 99.9
+	testDataType(variable)
+	variable = []string{}
+	testDataType(variable)
+}
diff --git a/cmd/type_assertion/main.go b/cmd/type_assertion/main.go
new file mode 100644
index 0000000..713c788
--- /dev/null
+++ b/cmd/type_assertion/main.go
@@ -0,0 +1,41 @@
+package main
+
+import (
+	"fmt"
+)
+
+func testString(variable interface{}) {
+	if val, ok := variable.(string); ok {
+		fmt.Println("It is a string : ", val)
+		return
+	}
+	fmt.Println("It is not a string")
+}
+
+func testInteger(variable interface{}) {
+	if val, ok := variable.(int); ok {
+		fmt.Println("It is an integer : ", val)
+		return
+	}
+	fmt.Println("It is not an integer")
+}
+
+func testFloat(variable interface{}) {
+	if val, ok := variable.(float64); ok {
+		fmt.Println("It is a float : ", val)
+		return
+	}
+	fmt.Println("It is not a float")
+}
+
+func main() {
+	var variable interface{}
+	variable = "Utkarsh"
+	testString(variable)
+	variable = 10
+	testInteger(variable)
+	variable = 99.9
+	testFloat(variable)
+	testString(variable)
+	testInteger(variable)
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..49502aa
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module github.com/utkarsh-josh/interface
+
+go 1.18
diff --git a/rectangle/rectangle.go b/rectangle/rectangle.go
new file mode 100644
index 0000000..7325144
--- /dev/null
+++ b/rectangle/rectangle.go
@@ -0,0 +1,30 @@
+package rectangle
+
+import (
+	"fmt"
+)
+
+type Rectangle interface {
+	Area()
+	Perimeter()
+}
+
+type rect struct {
+	length  int
+	breadth int
+}
+
+func NewRectangle(l, b int) Rectangle {
+	return &rect{
+		length:  l,
+		breadth: b,
+	}
+}
+
+func (r *rect) Area() {
+	fmt.Println("Area of rectangle : ", r.length*r.breadth)
+}
+
+func (r *rect) Perimeter() {
+	fmt.Println("Perimiter of rectangle : ", 2*(r.length+r.breadth))
+}