diff --git a/Lec13/go.mod b/Lec13/go.mod
new file mode 100644
index 0000000..a692304
--- /dev/null
+++ b/Lec13/go.mod
@@ -0,0 +1,3 @@
+module main.go
+
+go 1.24.4
diff --git a/Lec13/main.go b/Lec13/main.go
new file mode 100644
index 0000000..8a89758
--- /dev/null
+++ b/Lec13/main.go
@@ -0,0 +1,18 @@
+package main
+
+import "fmt"
+
+func main() {
+	command := "addition"
+	res := retFunc(command)
+	fmt.Println("Result is ",res(10,30))
+	fmt.Println("Type is %T",res)
+}
+
+func retFunc (a string) func(a,b int) int {
+	if a == "addition" {
+		return func(a,b int) int {return a + b}
+	} else {
+		return func(a,b int) int {return  a - b}
+	}
+}
diff --git a/Lec14/go.mod b/Lec14/go.mod
new file mode 100644
index 0000000..a692304
--- /dev/null
+++ b/Lec14/go.mod
@@ -0,0 +1,3 @@
+module main.go
+
+go 1.24.4
diff --git a/Lec14/main.go b/Lec14/main.go
new file mode 100644
index 0000000..ff91262
--- /dev/null
+++ b/Lec14/main.go
@@ -0,0 +1,27 @@
+package main
+
+import (
+	"fmt"
+	"strconv"
+)
+
+const (
+	A = 10
+	B = 11
+)
+
+func main() {
+
+	var constInt8 int8 = A
+	var constString string = strconv.Itoa(A)
+
+	fmt.Println("constInt8 is ",constInt8)
+	fmt.Println("constString is ",constString)
+
+}
+
+func checkConst() {
+	if A == 10 {
+		fmt.Printf("a is 10\n")
+	}
+}
diff --git a/Lec15/go.mod b/Lec15/go.mod
new file mode 100644
index 0000000..a692304
--- /dev/null
+++ b/Lec15/go.mod
@@ -0,0 +1,3 @@
+module main.go
+
+go 1.24.4
diff --git a/Lec15/main.go b/Lec15/main.go
new file mode 100644
index 0000000..246a5ec
--- /dev/null
+++ b/Lec15/main.go
@@ -0,0 +1,41 @@
+package main
+
+import "fmt"
+
+func main() {
+	// var variable int = 30
+	// var pointer *int = &variable
+
+	// fmt.Printf("Type of pointer %T\n",pointer)
+	// fmt.Printf("Value of pointer %v\n",pointer)
+
+	// secondPtr := &pointer
+	// fmt.Println("Pointer to pointer",secondPtr)
+
+
+	// zeroPtr := new(int)
+	// *zeroPtr += 40
+	// fmt.Println("Address is ",*zeroPtr)
+
+
+	// a := 10
+	// c := a
+	// b := &a
+	// *b += 2
+
+	// c++
+	// fmt.Printf("Val of A is %d and val of C is %d\n",a, c)
+	// fmt.Printf("Val of A after changing ref is %d",a)
+
+	sample := 1
+	// samplePtr := &sample
+	fmt.Println("Sample val is",sample)
+	kek(sample)
+	fmt.Println("Sample val is",sample)
+
+}
+
+func kek(val int) {
+	fmt.Println("Val of  val is",val)
+	val += 100
+}
\ No newline at end of file
diff --git a/Lec16/go.mod b/Lec16/go.mod
new file mode 100644
index 0000000..a692304
--- /dev/null
+++ b/Lec16/go.mod
@@ -0,0 +1,3 @@
+module main.go
+
+go 1.24.4
diff --git a/Lec16/main.go b/Lec16/main.go
new file mode 100644
index 0000000..75b7283
--- /dev/null
+++ b/Lec16/main.go
@@ -0,0 +1,15 @@
+package main
+
+import "fmt"
+
+func main() {
+	arr := [3]int{1,2,3}
+	fmt.Println("Initial array is ", arr)
+	mutation(&arr)
+	fmt.Println("Modified array is ", arr)
+}
+
+func mutation(arr *[3]int) {
+	(*arr)[0] = 900
+	(*arr)[2] = 1000
+}
\ No newline at end of file
diff --git a/Lec17/go.mod b/Lec17/go.mod
new file mode 100644
index 0000000..a692304
--- /dev/null
+++ b/Lec17/go.mod
@@ -0,0 +1,3 @@
+module main.go
+
+go 1.24.4
diff --git a/Lec17/main.go b/Lec17/main.go
new file mode 100644
index 0000000..13209d3
--- /dev/null
+++ b/Lec17/main.go
@@ -0,0 +1,3 @@
+package main
+
+func main() { }