diff --git a/Codes/Group A/Assignment-A3/A3.c b/Codes/Group A/Assignment-A3/A3.c
new file mode 100644
index 0000000..7076eb0
--- /dev/null
+++ b/Codes/Group A/Assignment-A3/A3.c	
@@ -0,0 +1,32 @@
+#include <jni.h>
+#include <stdio.h>
+#include "A3.h"
+
+JNIEXPORT jint JNICALL Java_A3_add(JNIEnv *env, jobject obj, jint a, jint b) {
+    jint result = a + b;
+    printf("\n%d + %d = %d\n", a, b, result);
+    return result; // Return the result
+}
+
+JNIEXPORT jint JNICALL Java_A3_sub(JNIEnv *env, jobject obj, jint a, jint b) {
+    jint result = a - b;
+    printf("\n%d - %d = %d\n", a, b, result);
+    return result; // Return the result
+}
+
+JNIEXPORT jint JNICALL Java_A3_mult(JNIEnv *env, jobject obj, jint a, jint b) {
+    jint result = a * b;
+    printf("\n%d * %d = %d\n", a, b, result);
+    return result; // Return the result
+}
+
+JNIEXPORT jint JNICALL Java_A3_div(JNIEnv *env, jobject obj, jint a, jint b) {
+    if (b == 0) {
+        printf("Error: Division by zero.\n");
+        return 0; // Return 0 or handle error appropriately
+    }
+    jint result = a / b;
+    printf("\n%d / %d = %d\n", a, b, result);
+    return result; // Return the result
+}
+
diff --git a/Codes/Group A/Assignment-A3/A3.java b/Codes/Group A/Assignment-A3/A3.java
new file mode 100644
index 0000000..e12fc79
--- /dev/null
+++ b/Codes/Group A/Assignment-A3/A3.java	
@@ -0,0 +1,45 @@
+import java.io.*;
+import java.util.*;
+
+class A3 {
+    static {
+        System.loadLibrary("A3");
+    }
+
+    private native int add(int a, int b);
+    private native int sub(int a, int b);
+    private native int mult(int a, int b);
+    private native int div(int a, int b);
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        int a, b, ch;
+
+        System.out.println("\nEnter value of a : ");
+        a = sc.nextInt();
+        System.out.println("\nEnter value of b : ");
+        b = sc.nextInt();
+
+        do {
+            System.out.println("\nENTER YOUR CHOICE : ");
+            ch = sc.nextInt();
+            switch (ch) {
+                case 1:
+                    new A3().add(a, b);
+                    break;
+                case 2:
+                    new A3().sub(a, b);
+                    break;
+                case 3:
+                    new A3().mult(a, b);
+                    break;
+                case 4:
+                    new A3().div(a, b);
+                    break;
+                default:
+                    System.out.println("Your choice is wrong.");
+            }
+        } while (ch < 5);
+    }
+}
+
diff --git a/Codes/Group A/Assignment-A3/README.md b/Codes/Group A/Assignment-A3/README.md
new file mode 100644
index 0000000..598df93
--- /dev/null
+++ b/Codes/Group A/Assignment-A3/README.md	
@@ -0,0 +1,36 @@
+## Steps to run this code
+
+These are the steps to run code for Assignment-A3.
+
+---
+
+> [!IMPORTANT]
+> I've tested this on Linux, thus I've included instructions for the same.
+
+### Prerequisites
+
+1. open-jdk (version 11 or higher)
+2. gcc
+3. Common sense
+
+### Steps
+
+1. Compile `A3.java`:
+```shell
+javac A3.java
+```
+
+2. Generate header file:
+```shell
+javac -h . A3.java
+```
+
+3. Compile C code:
+```shell
+gcc -shared -o libA3.so -fPIC -I"$JAVA_HOME/include" -I"$JAVA_HOME/include/linux" A3.c
+```
+
+4. Run program:
+```shell
+java -Djava.library.path=. A3
+```
diff --git a/README.md b/README.md
index d6cda5e..79db850 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,7 @@ This repository serves as a comprehensive resource for the Systems Programming a
     - [Code](https://git.kska.io/sppu-te-comp-content/SystemsProgrammingAndOperatingSystem/src/branch/main/Codes/Group%20A/Assignment-A1/Code-A1.py)
     - [Source file](https://git.kska.io/sppu-te-comp-content/SystemsProgrammingAndOperatingSystem/src/branch/main/Codes/Group%20A/Assignment-A1/source.txt)
 2. [Code-A2 - Pass 1 and Pass 2 of 2-Pass Macroprocessor](https://git.kska.io/sppu-te-comp-content/SystemsProgrammingAndOperatingSystem/src/branch/main/Codes/Group%20A/Code-A2.py)
+3. [Code-A3 - DLL](https://git.kska.io/sppu-te-comp-content/SystemsProgrammingAndOperatingSystem/src/branch/main/Codes/Group%20A/Assignment-A3/)
 
 ##### Group B
 5. [CPU Scheduling Algorithms: FCFS, SJF (Preemptive), Priority (Non-Preemptive) and Round Robin (Preemptive)](https://git.kska.io/sppu-te-comp-content/SystemsProgrammingAndOperatingSystem/src/branch/main/Codes/Group%20B/Assignment%20-%205)