diff --git a/lab4/src/pipes/important.cpp b/lab4/src/pipes/important.cpp
new file mode 100644
index 0000000..9f72711
--- /dev/null
+++ b/lab4/src/pipes/important.cpp
@@ -0,0 +1,283 @@
+#include <iostream>
+#include "important.h"
+#include <cstdint>
+#include <chrono>
+#include <fstream>
+
+using namespace std;
+
+struct image_t *S1_smoothen(struct image_t *input_image)
+{
+	// cout << input_image->width << input_image->height << " " <<  input_image->image_pixels << endl;
+	int width = input_image->width;
+	int height = input_image->height;
+
+	// memory allocation
+	struct image_t *smoother = new struct image_t;
+	smoother->height = height;
+	smoother->width = width;
+	smoother->image_pixels = new uint8_t **[height];
+	for (int i = 0; i < height; i++)
+	{
+		smoother->image_pixels[i] = new uint8_t *[width];
+		for (int j = 0; j < width; j++)
+			smoother->image_pixels[i][j] = new uint8_t[3];
+	}
+
+	for (int i = 1; i < height - 1; i++)
+	{
+		for (int j = 1; j < width - 1; j++)
+		{
+			for (int k = 0; k < 3; k++)
+			{
+				// image->image_pixels[i][j][k] = val;
+				//  edge cases
+				if (i == 0 && j == 0)
+				{ // i-1 and j - 1 doesnt exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i][j][k] / 4 + input_image->image_pixels[i][j + 1][k] / 4 + input_image->image_pixels[i + 1][j][k] / 4 + input_image->image_pixels[i + 1][j + 1][k] / 4);
+				}
+				else if (i == height - 1 && j == 0)
+				{ // i+1 and j-1 does not exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i - 1][j][k] / 4 + input_image->image_pixels[i - 1][j + 1][k] / 4 + input_image->image_pixels[i][j][k] / 4 + input_image->image_pixels[i][j + 1][k] / 4);
+				}
+
+				else if (i == 0 && j == width - 1)
+				{ // i-1 and j+1 does not exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i][j - 1][k] / 4 + input_image->image_pixels[i][j][k] / 4 + input_image->image_pixels[i + 1][j - 1][k] / 4 + input_image->image_pixels[i + 1][j][k] / 4);
+				}
+				else if (i == height - 1 && j == width - 1)
+				{ // i+1 and j+1 does not exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i - 1][j - 1][k] / 4 + input_image->image_pixels[i - 1][j][k] / 4 + input_image->image_pixels[i][j - 1][k] / 4 + input_image->image_pixels[i][j][k] / 4);
+				}
+				else if (i == 0)
+				{ // i - 1 does not exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i][j - 1][k] / 6 + input_image->image_pixels[i][j][k] / 6 + input_image->image_pixels[i][j + 1][k] / 6 + input_image->image_pixels[i + 1][j - 1][k] / 6 + input_image->image_pixels[i + 1][j][k] / 6 + input_image->image_pixels[i + 1][j + 1][k] / 6);
+				}
+
+				else if (j == 0)
+				{ // j -1 does not exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i - 1][j][k] / 6 + input_image->image_pixels[i - 1][j + 1][k] / 6 + input_image->image_pixels[i][j][k] / 6 + input_image->image_pixels[i][j + 1][k] / 6 + input_image->image_pixels[i + 1][j][k] / 6 + input_image->image_pixels[i + 1][j + 1][k] / 6);
+				}
+
+				else if (i == height - 1)
+				{ // i+1 does not exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i - 1][j - 1][k] / 6 + input_image->image_pixels[i - 1][j][k] / 6 + input_image->image_pixels[i - 1][j + 1][k] / 6 + input_image->image_pixels[i][j - 1][k] / 6 + input_image->image_pixels[i][j][k] / 6 + input_image->image_pixels[i][j + 1][k] / 6);
+				}
+				else if (j == width - 1)
+				{ // j + 1 does not exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i - 1][j - 1][k] / 6 + input_image->image_pixels[i - 1][j][k] / 6 + input_image->image_pixels[i][j - 1][k] / 6 + input_image->image_pixels[i][j][k] / 6 + input_image->image_pixels[i + 1][j - 1][k] / 6 + input_image->image_pixels[i + 1][j][k] / 6);
+				}
+				else
+				{
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i - 1][j - 1][k] / 9 + input_image->image_pixels[i - 1][j][k] / 9 + input_image->image_pixels[i - 1][j + 1][k] / 9 + input_image->image_pixels[i][j - 1][k] / 9 + input_image->image_pixels[i][j][k] / 9 + input_image->image_pixels[i][j + 1][k] / 9 + input_image->image_pixels[i + 1][j - 1][k] / 9 + input_image->image_pixels[i + 1][j][k] / 9 + input_image->image_pixels[i + 1][j + 1][k] / 9);
+				}
+			}
+		}
+	}
+
+	return smoother;
+}
+
+struct image_t *S2_find_details(struct image_t *input_image, struct image_t *smoothened_image)
+{
+	// TODO
+	int width = input_image->width;
+	int height = input_image->height;
+
+	struct image_t *details = new struct image_t;
+	details->height = height;
+	details->width = width;
+	details->image_pixels = new uint8_t **[height];
+
+	for (int i = 0; i < height; i++)
+	{
+		details->image_pixels[i] = new uint8_t *[width];
+		for (int j = 0; j < width; j++)
+			details->image_pixels[i][j] = new uint8_t[3];
+	}
+
+	for (int i = 1; i < height - 1; i++)
+	{
+		for (int j = 1; j < width - 1; j++)
+		{
+			for (int k = 0; k < 3; k++)
+			{
+				details->image_pixels[i][j][k] = max(0, input_image->image_pixels[i][j][k] - smoothened_image->image_pixels[i][j][k]);
+			}
+		}
+	}
+
+	return details;
+}
+
+struct image_t *S3_sharpen(struct image_t *input_image, struct image_t *details_image)
+{
+	// TODO
+	int width = input_image->width;
+	int height = input_image->height;
+
+	int a = 1;
+
+	struct image_t *sharp = new struct image_t;
+	sharp->height = height;
+	sharp->width = width;
+	sharp->image_pixels = new uint8_t **[height];
+
+	for (int i = 0; i < height; i++)
+	{
+		sharp->image_pixels[i] = new uint8_t *[width];
+		for (int j = 0; j < width; j++)
+			sharp->image_pixels[i][j] = new uint8_t[3];
+	}
+
+	for (int i = 1; i < height - 1; i++)
+	{
+		for (int j = 1; j < width - 1; j++)
+		{
+			for (int k = 0; k < 3; k++)
+			{
+				sharp->image_pixels[i][j][k] = min(255, input_image->image_pixels[i][j][k] + details_image->image_pixels[i][j][k]) * a;
+			}
+		}
+	}
+	return sharp; // TODO remove this line when adding your code
+}
+
+uint8_t skip_blanks_comments_while_reading(ifstream *read_stream) // returns the byte at the first position after the skipping of the blank space
+{
+	uint8_t val;
+	while (true)
+	{
+		val = read_stream->get();
+		if (val == '#')
+		{
+			while (val != '\n')
+			{
+				val = read_stream->get();
+			}
+		}
+		if (val == '\n' || val == ' ' || val == '\t')
+		{
+			continue;
+		}
+		else if (val != '#')
+			return val;
+	}
+	return val;
+}
+
+struct image_t *read_ppm_file(char *path_to_input_file)
+{
+	// cout << "input image file = " << path_to_input_file << "\n";
+
+	ifstream read_stream(path_to_input_file, ios::binary | ios::in);
+
+	if (read_stream.is_open())
+	{
+		struct image_t *image = new struct image_t;
+
+		uint8_t val = skip_blanks_comments_while_reading(&read_stream); // 'P'
+		val = read_stream.get();										//'6'
+
+		// width
+		val = skip_blanks_comments_while_reading(&read_stream);
+		while (true)
+		{
+			if (val == ' ' || val == '\t' || val == '\n')
+				break;
+			image->width = image->width * 10 + (val - '0');
+			val = read_stream.get();
+		}
+		// cout << "width = " << image->width << "\n";
+
+		// height
+		val = skip_blanks_comments_while_reading(&read_stream);
+		while (true)
+		{
+			if (val == ' ' || val == '\t' || val == '\n')
+				break;
+			image->height = image->height * 10 + (val - '0');
+			val = read_stream.get();
+		}
+		// cout << "height = " << image->height << "\n";
+
+		image->image_pixels = new uint8_t **[image->height];
+		for (int i = 0; i < image->height; i++)
+		{
+			image->image_pixels[i] = new uint8_t *[image->width];
+			for (int j = 0; j < image->width; j++)
+				image->image_pixels[i][j] = new uint8_t[3];
+		}
+
+		// maxval
+		val = skip_blanks_comments_while_reading(&read_stream);
+		while (true)
+		{
+			if (val == ' ' || val == '\t' || val == '\n')
+				break;
+			val = read_stream.get();
+		}
+
+		// get pixel values
+		val = skip_blanks_comments_while_reading(&read_stream);
+		for (int i = 0; i < image->height; i++)
+		{
+			for (int j = 0; j < image->width; j++)
+			{
+				for (int k = 0; k < 3; k++)
+				{
+					image->image_pixels[i][j][k] = val;
+					val = read_stream.get(); // assuming maxval of <=255
+				}
+			}
+		}
+		// read_stream.seekg(-1, ios_base::cur);
+		// read_stream.read(((char*)image->image_pixels), image->height * image->width * 3); //assuming maxval of <=255
+
+		read_stream.close();
+
+		return image;
+	}
+	else
+	{
+		cerr << "failed to open file " << path_to_input_file << "\n\n";
+		exit(1);
+	}
+}
+
+void write_ppm_file(char *path_to_output_file, struct image_t *image)
+{
+	// cout << "output image file = " << path_to_output_file << "\n";
+
+	ofstream write_stream(path_to_output_file, ios::binary | ios::out);
+
+	if (write_stream.is_open())
+	{
+		write_stream.write("P6\n", 3);
+		std::string width_string = std::to_string(image->width);
+		// cout << "width = " << width_string << "\n";
+		write_stream.write(width_string.c_str(), width_string.length());
+		write_stream.write(" ", 1);
+		std::string height_string = std::to_string(image->height);
+		// cout << "height = " << height_string << "\n";
+		write_stream.write(height_string.c_str(), height_string.length());
+		write_stream.write("\n255\n", 5);
+		for (int i = 0; i < image->height; i++)
+		{
+			for (int j = 0; j < image->width; j++)
+			{
+				for (int k = 0; k < 3; k++)
+				{
+					write_stream.put(image->image_pixels[i][j][k]); // assuming maxval of <=255
+				}
+			}
+		}
+		// write_stream.write(((char*)image->image_pixels), image->height * image->width * 3);
+		write_stream.close();
+	}
+	else
+	{
+		cerr << "failed to open file " << path_to_output_file << "\n\n";
+		exit(1);
+	}
+}
diff --git a/lab4/src/pipes/important.h b/lab4/src/pipes/important.h
new file mode 100644
index 0000000..b536603
--- /dev/null
+++ b/lab4/src/pipes/important.h
@@ -0,0 +1,19 @@
+#ifndef IMPORTANT_H
+#define IMPORTANT_H
+#include <cstdint>
+
+struct image_t
+{
+	int width;
+	int height;
+	uint8_t*** image_pixels;
+};
+
+struct image_t* S1_smoothen(struct image_t *input_image);
+struct image_t* S2_find_details(struct image_t *input_image, struct image_t *smoothened_image);
+struct image_t* S3_sharpen(struct image_t *input_image, struct image_t *details_image);
+
+struct image_t* read_ppm_file(char* path_to_input_file);
+void write_ppm_file(char* path_to_output_file, struct image_t* image);
+
+#endif
\ No newline at end of file
diff --git a/lab4/src/shared.cpp b/lab4/src/shared.cpp
deleted file mode 100644
index 5cfbb68..0000000
--- a/lab4/src/shared.cpp
+++ /dev/null
@@ -1,254 +0,0 @@
-#include "important.h"
-#include <iostream>
-#include <cstdint>
-#include <chrono>
-#include <fstream>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/wait.h>
-#include <unistd.h>
-#include<sys/mman.h>
-#include<sys/stat.h>
-#include<fcntl.h>
-#include<semaphore.h>
-
-using namespace std;
-
-int main(int argc, char *argv[]) {
-
-	// if(argc != 3)
-	// {
-	// 	cout << "usage: ./a.out <path-to-original-image> <path-to-transformed-image>\n\n";
-	// 	exit(0);
-	// }
-
-    // struct image_t *input_image = read_ppm_file(argv[1]);
-
-    const char *shm1_name = "/shm_parent_child";
-    const char *shm2_name = "/shm_child_grandchild";
-    const char *sem1_name = "/sem_parent_child";
-    const char *sem2_name = "/sem_child_grandchild";
-
-    int shm_fd = shm_open(shm1_name, O_CREAT | O_RDWR, 0666);
-    if (shm_fd == -1) {
-        perror("shm_open");
-        return 1;
-    }
-
-    // Resize the shared memory object to the desired size
-    if (ftruncate(shm_fd, size) == -1) {
-        perror("ftruncate");
-        return 1;
-    }
-
-    // Map the shared memory object into the process address space
-    void *ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, 0);
-    if (ptr == MAP_FAILED) {
-        perror("mmap");
-        return 1;
-    }
-
-    sem_t *sem_parent_child = sem_open(sem1_name, O_CREAT, 0666, 0); // Initially locked (0)
-    sem_t *sem_child_grandchild = sem_open(sem2_name, O_CREAT, 0666, 0); // Initially locked (0)
-
-    if (sem_parent_child == SEM_FAILED || sem_child_grandchild == SEM_FAILED) {
-        perror("sem_open failed");
-        exit(EXIT_FAILURE);
-    }
-
-
-    // size_t size = input_image->height * input_image->width * 3 * sizeof(uint8_t);
-    size_t size = 1024;
-
-	pid_t CHILD;
-	CHILD = fork();
-	if (CHILD == -1) {
-		perror("fork failed!");
-		exit(EXIT_FAILURE);
-	}
-
-	// Parent Process
-	if(CHILD != 0){
-
-        char buffer[1024] = {'p', 'a', 'c', 'k', 'e', 't', '\0'};
-        buffer[7] = '\0';
-
-        // Write data to the shared memory
-        for(int i = 1; i < 5; i++){
-		    // printf("parent writing to shm\n");
-            buffer[6] = '0' + i;
-            memcpy(ptr, buffer, 1024);  // Copy 1024 bytes to shared memory
-
-            // Optional: Print what is being written to shared memory for verification
-            printf("P - Writing to shared memory: %s\n", (char *)ptr);
-            sem_post(sem_parent_child);
-            sem_wait(sem_child_grandchild);
-        }
-
-        // Unmap the shared memory object
-        if (munmap(ptr, size) == -1) {
-            perror("munmap");
-            return 1;
-        }
-
-        // Close the shared memory file descriptor
-        if (close(shm_fd) == -1) {
-            perror("close");
-            return 1;
-        }
-
-        sem_close(sem_parent_child);
-        sem_close(sem_child_grandchild);
-		wait(NULL);                /* Wait for child */
-	}
-
-	// Child process
-	else if (CHILD == 0) {    /* Child reads from pipe */
-		pid_t GRAND_CHILD = fork();
-
-		if (GRAND_CHILD == -1) {
-			perror("fork failed!");
-			exit(EXIT_FAILURE);
-		}
-
-		// Child Process
-		if(GRAND_CHILD != 0){
-            int shm_fd = shm_open(shm1_name, O_CREAT | O_RDWR, 0666);
-            if (shm_fd == -1) {
-                perror("shm_open");
-                return 1;
-            }
-
-            // Resize the shared memory object to the desired size
-            if (ftruncate(shm_fd, size) == -1) {
-                perror("ftruncate");
-                return 1;
-            }
-
-            // Map the shared memory object into the process address space
-            void *ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, 0);
-            if (ptr == MAP_FAILED) {
-                perror("mmap");
-                return 1;
-            }
-
-            int shm2_fd = shm_open(shm2_name, O_CREAT | O_RDWR, 0666);
-            if (shm2_fd == -1) {
-                perror("shm_open");
-                return 1;
-            }
-
-            // Resize the shared memory object to the desired size
-            if (ftruncate(shm2_fd, size) == -1) {
-                perror("ftruncate");
-                return 1;
-            }
-
-            // Map the shared memory object into the process address space
-            void *ptr2 = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, shm2_fd, 0);
-            if (ptr2 == MAP_FAILED) {
-                perror("mmap");
-                return 1;
-            }
-
-            for(int i=0; i<5; i++){
-                // printf("Child reading from shm1 and writing to shm2...\n");
-                sem_wait(sem_parent_child);
-                // Print the contents of the shared memory
-                char *packet = (char *)ptr;
-                printf("C - Shared memory contents: %s\n", packet);
-                // char buffer[1024];
-                // strncpy(buffer, (char *)ptr, 1024);
-                memcpy(ptr2, ptr, 1024);
-                sem_post(sem_child_grandchild); // Signal parent
-            }
-
-            // Unmap the shared memory object
-            if (munmap(ptr, size) == -1) {
-                perror("munmap");
-                return 1;
-            }
-
-            // Close the shared memory file descriptor
-            if (close(shm_fd) == -1) {
-                perror("close");
-                return 1;
-            }
-			// printf("child writing to shm\n");
-
-            // Unmap the shared memory object
-            if (munmap(ptr2, size) == -1) {
-                perror("munmap");
-                return 1;
-            }
-
-            // Close the shared memory file descriptor
-            if (close(shm2_fd) == -1) {
-                perror("close");
-                return 1;
-            }
-
-            shm_unlink(shm1_name);
-            sem_close(sem_parent_child);
-            sem_close(sem_child_grandchild);
-			wait(NULL);
-			exit(EXIT_SUCCESS);
-		}
-
-		// GrandChild Process
-		else if (GRAND_CHILD == 0) {    /* GrandChild reads from pipe */
-            int shm2_fd = shm_open(shm2_name, O_CREAT | O_RDWR, 0666);
-            if (shm2_fd == -1) {
-                perror("shm_open");
-                return 1;
-            }
-
-            // Resize the shared memory object to the desired size
-            if (ftruncate(shm2_fd, size) == -1) {
-                perror("ftruncate");
-                return 1;
-            }
-
-            // Map the shared memory object into the process address space
-            void *ptr2 = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, shm2_fd, 0);
-            if (ptr2 == MAP_FAILED) {
-                perror("mmap");
-                return 1;
-            }
-
-            for(int i=0; i<5; i++){
-                sem_wait(sem_child_grandchild);
-                // Print the contents of the shared memory
-                // printf("Grandchild reading from shm...\n");
-                printf("GC - Shared memory contents: %s\n", (char *)ptr2);
-            }
-
-            // Unmap the shared memory object
-            if (munmap(ptr2, size) == -1) {
-                perror("munmap");
-                return 1;
-            }
-
-            // Close the shared memory file descriptor
-            if (close(shm2_fd) == -1) {
-                perror("close");
-                return 1;
-            }
-
-            shm_unlink(shm2_name);
-			sem_close(sem_parent_child);
-            sem_close(sem_child_grandchild);
-            exit(EXIT_SUCCESS);
-		}
-	}
-
-    sem_close(sem_parent_child);
-    sem_close(sem_child_grandchild);
-    sem_unlink(sem1_name);
-    sem_unlink(sem2_name);
-
-    cout << "success" << endl;
-    return 0;
-}
\ No newline at end of file
diff --git a/lab4/src/shm1.cpp b/lab4/src/shm1.cpp
deleted file mode 100644
index 977185a..0000000
--- a/lab4/src/shm1.cpp
+++ /dev/null
@@ -1,53 +0,0 @@
-#include<stdio.h>
-#include<sys/mman.h>
-#include<sys/stat.h>
-#include<fcntl.h>
-#include<unistd.h>
-
-int main() {
-    const char *name = "/my_shared_memory";
-    int shm_fd = shm_open(name, O_CREAT | O_RDWR, 0666);
-    if (shm_fd == -1) {
-        perror("shm_open");
-        return 1;
-    }
-
-    // Set the size of the shared memory region
-    size_t size = 1024;
-
-    // Resize the shared memory object to the desired size
-    if (ftruncate(shm_fd, size) == -1) {
-        perror("ftruncate");
-        return 1;
-    }
-
-    // Map the shared memory object into the process address space
-    void *ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, 0);
-    if (ptr == MAP_FAILED) {
-        perror("mmap");
-        return 1;
-    }
-
-    // Write data to the shared memory
-    sprintf((char *)ptr, "Hello, shared memory!");
-
-    // Unmap the shared memory object
-    if (munmap(ptr, size) == -1) {
-        perror("munmap");
-        return 1;
-    }
-
-    // Close the shared memory file descriptor
-    if (close(shm_fd) == -1) {
-        perror("close");
-        return 1;
-    }
-
-    // Unlink the shared memory object
-    if (shm_unlink(name) == -1) {
-        perror("shm_unlink");
-        return 1;
-    }
-
-    return 0;
-}
diff --git a/lab4/src/shm2.cpp b/lab4/src/shm2.cpp
deleted file mode 100644
index aec2d26..0000000
--- a/lab4/src/shm2.cpp
+++ /dev/null
@@ -1,50 +0,0 @@
-/* reader */
-#include<stdio.h>
-#include<sys/mman.h>
-#include<sys/stat.h>
-#include<fcntl.h>
-#include<unistd.h>
-
-int main() {
-    const char *name = "/my_shared_memory";
-    int shm_fd = shm_open(name, O_CREAT | O_RDWR, 0666);
-    if (shm_fd == -1) {
-        perror("shm_open");
-        return 1;
-    }
-
-    // Set the size of the shared memory region
-    size_t size = 1024;
-
-    // Resize the shared memory object to the desired size
-    if (ftruncate(shm_fd, size) == -1) {
-        perror("ftruncate");
-        return 1;
-    }
-
-    // Map the shared memory object into the process address space
-    void *ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, 0);
-    if (ptr == MAP_FAILED) {
-        perror("mmap");
-        return 1;
-    }
-
-    sleep(2);
-
-    // Print the contents of the shared memory
-    printf("Shared memory contents: %s\n", (char *)ptr);
-
-    // Unmap the shared memory object
-    if (munmap(ptr, size) == -1) {
-        perror("munmap");
-        return 1;
-    }
-
-    // Close the shared memory file descriptor
-    if (close(shm_fd) == -1) {
-        perror("close");
-        return 1;
-    }
-
-    return 0;
-}
diff --git a/lab4/src/threads/important.cpp b/lab4/src/threads/important.cpp
new file mode 100644
index 0000000..9f72711
--- /dev/null
+++ b/lab4/src/threads/important.cpp
@@ -0,0 +1,283 @@
+#include <iostream>
+#include "important.h"
+#include <cstdint>
+#include <chrono>
+#include <fstream>
+
+using namespace std;
+
+struct image_t *S1_smoothen(struct image_t *input_image)
+{
+	// cout << input_image->width << input_image->height << " " <<  input_image->image_pixels << endl;
+	int width = input_image->width;
+	int height = input_image->height;
+
+	// memory allocation
+	struct image_t *smoother = new struct image_t;
+	smoother->height = height;
+	smoother->width = width;
+	smoother->image_pixels = new uint8_t **[height];
+	for (int i = 0; i < height; i++)
+	{
+		smoother->image_pixels[i] = new uint8_t *[width];
+		for (int j = 0; j < width; j++)
+			smoother->image_pixels[i][j] = new uint8_t[3];
+	}
+
+	for (int i = 1; i < height - 1; i++)
+	{
+		for (int j = 1; j < width - 1; j++)
+		{
+			for (int k = 0; k < 3; k++)
+			{
+				// image->image_pixels[i][j][k] = val;
+				//  edge cases
+				if (i == 0 && j == 0)
+				{ // i-1 and j - 1 doesnt exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i][j][k] / 4 + input_image->image_pixels[i][j + 1][k] / 4 + input_image->image_pixels[i + 1][j][k] / 4 + input_image->image_pixels[i + 1][j + 1][k] / 4);
+				}
+				else if (i == height - 1 && j == 0)
+				{ // i+1 and j-1 does not exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i - 1][j][k] / 4 + input_image->image_pixels[i - 1][j + 1][k] / 4 + input_image->image_pixels[i][j][k] / 4 + input_image->image_pixels[i][j + 1][k] / 4);
+				}
+
+				else if (i == 0 && j == width - 1)
+				{ // i-1 and j+1 does not exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i][j - 1][k] / 4 + input_image->image_pixels[i][j][k] / 4 + input_image->image_pixels[i + 1][j - 1][k] / 4 + input_image->image_pixels[i + 1][j][k] / 4);
+				}
+				else if (i == height - 1 && j == width - 1)
+				{ // i+1 and j+1 does not exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i - 1][j - 1][k] / 4 + input_image->image_pixels[i - 1][j][k] / 4 + input_image->image_pixels[i][j - 1][k] / 4 + input_image->image_pixels[i][j][k] / 4);
+				}
+				else if (i == 0)
+				{ // i - 1 does not exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i][j - 1][k] / 6 + input_image->image_pixels[i][j][k] / 6 + input_image->image_pixels[i][j + 1][k] / 6 + input_image->image_pixels[i + 1][j - 1][k] / 6 + input_image->image_pixels[i + 1][j][k] / 6 + input_image->image_pixels[i + 1][j + 1][k] / 6);
+				}
+
+				else if (j == 0)
+				{ // j -1 does not exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i - 1][j][k] / 6 + input_image->image_pixels[i - 1][j + 1][k] / 6 + input_image->image_pixels[i][j][k] / 6 + input_image->image_pixels[i][j + 1][k] / 6 + input_image->image_pixels[i + 1][j][k] / 6 + input_image->image_pixels[i + 1][j + 1][k] / 6);
+				}
+
+				else if (i == height - 1)
+				{ // i+1 does not exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i - 1][j - 1][k] / 6 + input_image->image_pixels[i - 1][j][k] / 6 + input_image->image_pixels[i - 1][j + 1][k] / 6 + input_image->image_pixels[i][j - 1][k] / 6 + input_image->image_pixels[i][j][k] / 6 + input_image->image_pixels[i][j + 1][k] / 6);
+				}
+				else if (j == width - 1)
+				{ // j + 1 does not exist
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i - 1][j - 1][k] / 6 + input_image->image_pixels[i - 1][j][k] / 6 + input_image->image_pixels[i][j - 1][k] / 6 + input_image->image_pixels[i][j][k] / 6 + input_image->image_pixels[i + 1][j - 1][k] / 6 + input_image->image_pixels[i + 1][j][k] / 6);
+				}
+				else
+				{
+					smoother->image_pixels[i][j][k] = (input_image->image_pixels[i - 1][j - 1][k] / 9 + input_image->image_pixels[i - 1][j][k] / 9 + input_image->image_pixels[i - 1][j + 1][k] / 9 + input_image->image_pixels[i][j - 1][k] / 9 + input_image->image_pixels[i][j][k] / 9 + input_image->image_pixels[i][j + 1][k] / 9 + input_image->image_pixels[i + 1][j - 1][k] / 9 + input_image->image_pixels[i + 1][j][k] / 9 + input_image->image_pixels[i + 1][j + 1][k] / 9);
+				}
+			}
+		}
+	}
+
+	return smoother;
+}
+
+struct image_t *S2_find_details(struct image_t *input_image, struct image_t *smoothened_image)
+{
+	// TODO
+	int width = input_image->width;
+	int height = input_image->height;
+
+	struct image_t *details = new struct image_t;
+	details->height = height;
+	details->width = width;
+	details->image_pixels = new uint8_t **[height];
+
+	for (int i = 0; i < height; i++)
+	{
+		details->image_pixels[i] = new uint8_t *[width];
+		for (int j = 0; j < width; j++)
+			details->image_pixels[i][j] = new uint8_t[3];
+	}
+
+	for (int i = 1; i < height - 1; i++)
+	{
+		for (int j = 1; j < width - 1; j++)
+		{
+			for (int k = 0; k < 3; k++)
+			{
+				details->image_pixels[i][j][k] = max(0, input_image->image_pixels[i][j][k] - smoothened_image->image_pixels[i][j][k]);
+			}
+		}
+	}
+
+	return details;
+}
+
+struct image_t *S3_sharpen(struct image_t *input_image, struct image_t *details_image)
+{
+	// TODO
+	int width = input_image->width;
+	int height = input_image->height;
+
+	int a = 1;
+
+	struct image_t *sharp = new struct image_t;
+	sharp->height = height;
+	sharp->width = width;
+	sharp->image_pixels = new uint8_t **[height];
+
+	for (int i = 0; i < height; i++)
+	{
+		sharp->image_pixels[i] = new uint8_t *[width];
+		for (int j = 0; j < width; j++)
+			sharp->image_pixels[i][j] = new uint8_t[3];
+	}
+
+	for (int i = 1; i < height - 1; i++)
+	{
+		for (int j = 1; j < width - 1; j++)
+		{
+			for (int k = 0; k < 3; k++)
+			{
+				sharp->image_pixels[i][j][k] = min(255, input_image->image_pixels[i][j][k] + details_image->image_pixels[i][j][k]) * a;
+			}
+		}
+	}
+	return sharp; // TODO remove this line when adding your code
+}
+
+uint8_t skip_blanks_comments_while_reading(ifstream *read_stream) // returns the byte at the first position after the skipping of the blank space
+{
+	uint8_t val;
+	while (true)
+	{
+		val = read_stream->get();
+		if (val == '#')
+		{
+			while (val != '\n')
+			{
+				val = read_stream->get();
+			}
+		}
+		if (val == '\n' || val == ' ' || val == '\t')
+		{
+			continue;
+		}
+		else if (val != '#')
+			return val;
+	}
+	return val;
+}
+
+struct image_t *read_ppm_file(char *path_to_input_file)
+{
+	// cout << "input image file = " << path_to_input_file << "\n";
+
+	ifstream read_stream(path_to_input_file, ios::binary | ios::in);
+
+	if (read_stream.is_open())
+	{
+		struct image_t *image = new struct image_t;
+
+		uint8_t val = skip_blanks_comments_while_reading(&read_stream); // 'P'
+		val = read_stream.get();										//'6'
+
+		// width
+		val = skip_blanks_comments_while_reading(&read_stream);
+		while (true)
+		{
+			if (val == ' ' || val == '\t' || val == '\n')
+				break;
+			image->width = image->width * 10 + (val - '0');
+			val = read_stream.get();
+		}
+		// cout << "width = " << image->width << "\n";
+
+		// height
+		val = skip_blanks_comments_while_reading(&read_stream);
+		while (true)
+		{
+			if (val == ' ' || val == '\t' || val == '\n')
+				break;
+			image->height = image->height * 10 + (val - '0');
+			val = read_stream.get();
+		}
+		// cout << "height = " << image->height << "\n";
+
+		image->image_pixels = new uint8_t **[image->height];
+		for (int i = 0; i < image->height; i++)
+		{
+			image->image_pixels[i] = new uint8_t *[image->width];
+			for (int j = 0; j < image->width; j++)
+				image->image_pixels[i][j] = new uint8_t[3];
+		}
+
+		// maxval
+		val = skip_blanks_comments_while_reading(&read_stream);
+		while (true)
+		{
+			if (val == ' ' || val == '\t' || val == '\n')
+				break;
+			val = read_stream.get();
+		}
+
+		// get pixel values
+		val = skip_blanks_comments_while_reading(&read_stream);
+		for (int i = 0; i < image->height; i++)
+		{
+			for (int j = 0; j < image->width; j++)
+			{
+				for (int k = 0; k < 3; k++)
+				{
+					image->image_pixels[i][j][k] = val;
+					val = read_stream.get(); // assuming maxval of <=255
+				}
+			}
+		}
+		// read_stream.seekg(-1, ios_base::cur);
+		// read_stream.read(((char*)image->image_pixels), image->height * image->width * 3); //assuming maxval of <=255
+
+		read_stream.close();
+
+		return image;
+	}
+	else
+	{
+		cerr << "failed to open file " << path_to_input_file << "\n\n";
+		exit(1);
+	}
+}
+
+void write_ppm_file(char *path_to_output_file, struct image_t *image)
+{
+	// cout << "output image file = " << path_to_output_file << "\n";
+
+	ofstream write_stream(path_to_output_file, ios::binary | ios::out);
+
+	if (write_stream.is_open())
+	{
+		write_stream.write("P6\n", 3);
+		std::string width_string = std::to_string(image->width);
+		// cout << "width = " << width_string << "\n";
+		write_stream.write(width_string.c_str(), width_string.length());
+		write_stream.write(" ", 1);
+		std::string height_string = std::to_string(image->height);
+		// cout << "height = " << height_string << "\n";
+		write_stream.write(height_string.c_str(), height_string.length());
+		write_stream.write("\n255\n", 5);
+		for (int i = 0; i < image->height; i++)
+		{
+			for (int j = 0; j < image->width; j++)
+			{
+				for (int k = 0; k < 3; k++)
+				{
+					write_stream.put(image->image_pixels[i][j][k]); // assuming maxval of <=255
+				}
+			}
+		}
+		// write_stream.write(((char*)image->image_pixels), image->height * image->width * 3);
+		write_stream.close();
+	}
+	else
+	{
+		cerr << "failed to open file " << path_to_output_file << "\n\n";
+		exit(1);
+	}
+}
diff --git a/lab4/src/threads/important.h b/lab4/src/threads/important.h
new file mode 100644
index 0000000..b536603
--- /dev/null
+++ b/lab4/src/threads/important.h
@@ -0,0 +1,19 @@
+#ifndef IMPORTANT_H
+#define IMPORTANT_H
+#include <cstdint>
+
+struct image_t
+{
+	int width;
+	int height;
+	uint8_t*** image_pixels;
+};
+
+struct image_t* S1_smoothen(struct image_t *input_image);
+struct image_t* S2_find_details(struct image_t *input_image, struct image_t *smoothened_image);
+struct image_t* S3_sharpen(struct image_t *input_image, struct image_t *details_image);
+
+struct image_t* read_ppm_file(char* path_to_input_file);
+void write_ppm_file(char* path_to_output_file, struct image_t* image);
+
+#endif
\ No newline at end of file