diff --git a/OS/C/Week10/q2.c b/OS/C/Week10/q2.c
index e69de29..45d1079 100644
--- a/OS/C/Week10/q2.c
+++ b/OS/C/Week10/q2.c
@@ -0,0 +1,169 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h> // For INT_MAX
+
+// Structure to represent a frame and its last used time
+typedef struct {
+    int page_number;
+    int last_used_time;
+} Frame;
+
+// Function to find if a page exists in frames and return its index
+// Also updates the last_used_time if found
+int find_page(Frame frames[], int n_frames, int page, int current_time) {
+    for (int i = 0; i < n_frames; i++) {
+        if (frames[i].page_number == page) {
+            frames[i].last_used_time = current_time; // Update time on hit
+            return i; // Page found (Hit)
+        }
+    }
+    return -1; // Page not found (Fault)
+}
+
+// Function to find the index of the Least Recently Used (LRU) page
+int find_lru_index(Frame frames[], int n_frames) {
+    int min_time = INT_MAX;
+    int lru_index = 0;
+    for (int i = 0; i < n_frames; i++) {
+        // Frame must contain a valid page (not -1)
+        if (frames[i].page_number != -1 && frames[i].last_used_time < min_time) {
+            min_time = frames[i].last_used_time;
+            lru_index = i;
+        }
+    }
+    return lru_index;
+}
+
+// Function to print the current state of frames
+void print_frames(Frame frames[], int n_frames) {
+    printf("[");
+    for (int i = 0; i < n_frames; i++) {
+        if (frames[i].page_number == -1) {
+            printf(" - ");
+        } else {
+            printf(" %d ", frames[i].page_number);
+        }
+    }
+    printf("]\n");
+}
+
+int main() {
+    int n_frames, n_pages;
+    int *pages = NULL; // Reference string
+    Frame *frames = NULL; // Frames in memory
+
+    int page_faults = 0;
+    int page_hits = 0;
+    int current_time = 0; // Counter to track usage time
+    int frame_idx = 0; // Index for filling empty frames initially
+
+    // 1. Get Inputs
+    printf("Enter the number of frames: ");
+    if (scanf("%d", &n_frames) != 1 || n_frames <= 0) {
+        fprintf(stderr, "Error: Invalid number of frames.\n");
+        return 1;
+    }
+
+    printf("Enter the number of pages in the reference string: ");
+    if (scanf("%d", &n_pages) != 1 || n_pages <= 0) {
+        fprintf(stderr, "Error: Invalid number of pages.\n");
+        return 1;
+    }
+
+    // 2. Allocate Memory
+    pages = (int *)malloc(n_pages * sizeof(int));
+    if (pages == NULL) {
+        perror("Failed to allocate memory for pages");
+        return 1;
+    }
+
+    frames = (Frame *)malloc(n_frames * sizeof(Frame));
+    if (frames == NULL) {
+        perror("Failed to allocate memory for frames");
+        free(pages); // Clean up already allocated memory
+        return 1;
+    }
+
+    printf("Enter the page reference string (space-separated %d integers):\n", n_pages);
+    for (int i = 0; i < n_pages; i++) {
+        if (scanf("%d", &pages[i]) != 1) {
+             fprintf(stderr, "Error reading page reference string.\n");
+             free(pages);
+             free(frames);
+             return 1;
+        }
+    }
+
+    // 3. Initialize Frames
+    for (int i = 0; i < n_frames; i++) {
+        frames[i].page_number = -1; // -1 indicates empty frame
+        frames[i].last_used_time = -1; // Initialize time
+    }
+
+    printf("\n--- LRU Simulation Start ---\n");
+    printf("Frames: %d | Reference String Length: %d\n\n", n_frames, n_pages);
+
+    // 4. Process Page References
+    for (int i = 0; i < n_pages; i++) {
+        current_time++; // Increment time step for each reference
+        int current_page = pages[i];
+        printf("Ref: %d -> ", current_page);
+
+        int found_index = find_page(frames, n_frames, current_page, current_time);
+
+        if (found_index != -1) {
+            // Page Hit
+            page_hits++;
+            printf("Hit   ");
+        } else {
+            // Page Fault
+            page_faults++;
+            printf("Fault ");
+
+            // Find a place for the new page
+            int replace_index = -1;
+
+            // Check for an empty frame first
+            for(int k=0; k < n_frames; k++){
+                if(frames[k].page_number == -1){
+                    replace_index = k;
+                    break;
+                }
+            }
+
+            if (replace_index != -1) {
+                // Use the empty frame
+                frames[replace_index].page_number = current_page;
+                frames[replace_index].last_used_time = current_time;
+                 printf("(loaded into empty frame %d) ", replace_index);
+            } else {
+                // No empty frames, find LRU page to replace
+                replace_index = find_lru_index(frames, n_frames);
+                printf("(replaced P%d in frame %d) ", frames[replace_index].page_number, replace_index);
+                frames[replace_index].page_number = current_page;
+                frames[replace_index].last_used_time = current_time;
+            }
+        }
+        print_frames(frames, n_frames); // Show frame status after each step
+    }
+
+    // 5. Output Results
+    printf("\n--- LRU Simulation End ---\n");
+    printf("Total Page References: %d\n", n_pages);
+    printf("Total Page Hits:    %d\n", page_hits);
+    printf("Total Page Faults:  %d\n", page_faults);
+    if (n_pages > 0) {
+        printf("Hit Rate:           %.2f%%\n", (double)page_hits / n_pages * 100.0);
+        printf("Fault Rate:         %.2f%%\n", (double)page_faults / n_pages * 100.0);
+    } else {
+        printf("Hit Rate:           N/A\n");
+        printf("Fault Rate:         N/A\n");
+    }
+
+
+    // 6. Free Memory
+    free(pages);
+    free(frames);
+
+    return 0;
+}
diff --git a/OS/C/Week10/qq1.c b/OS/C/Week10/qq1.c
new file mode 100644
index 0000000..72d05c3
--- /dev/null
+++ b/OS/C/Week10/qq1.c
@@ -0,0 +1,176 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+// Function to check if a page exists in frames
+bool isPagePresent(int* frames, int num_frames, int page) {
+    for (int i = 0; i < num_frames; i++) {
+        if (frames[i] == page) {
+            return true;
+        }
+    }
+    return false;
+}
+
+// FIFO Page Replacement Algorithm
+void fifo(int* reference_string, int num_pages, int num_frames) {
+    int* frames = (int*)malloc(num_frames * sizeof(int));
+    int page_faults = 0;
+    int frame_index = 0;
+
+    // Initialize frames with -1 (indicating empty)
+    for (int i = 0; i < num_frames; i++) {
+        frames[i] = -1;
+    }
+
+    printf("\nFIFO Page Replacement Algorithm:\n");
+    printf("Reference String: ");
+    for (int i = 0; i < num_pages; i++) {
+        printf("%d ", reference_string[i]);
+    }
+    printf("\n\n");
+
+    for (int i = 0; i < num_pages; i++) {
+        printf("Page %d: ", reference_string[i]);
+
+        // Check if page already exists in frames
+        if (!isPagePresent(frames, num_frames, reference_string[i])) {
+            // Replace page at current frame_index
+            frames[frame_index] = reference_string[i];
+            frame_index = (frame_index + 1) % num_frames;
+            page_faults++;
+
+            printf("Page Fault! Frames: ");
+        } else {
+            printf("No Page Fault. Frames: ");
+        }
+
+        // Print current state of frames
+        for (int j = 0; j < num_frames; j++) {
+            if (frames[j] == -1) {
+                printf("[ ] ");
+            } else {
+                printf("[%d] ", frames[j]);
+            }
+        }
+        printf("\n");
+    }
+
+    printf("\nTotal Page Faults (FIFO): %d\n", page_faults);
+    free(frames);
+}
+
+// Function to find index of page that will be used farthest in future
+int findOptimalPage(int* reference_string, int* frames, int num_frames, int num_pages, int current_position) {
+    int farthest = -1;
+    int index = -1;
+
+    for (int i = 0; i < num_frames; i++) {
+        int j;
+        for (j = current_position + 1; j < num_pages; j++) {
+            if (frames[i] == reference_string[j]) {
+                if (j > farthest) {
+                    farthest = j;
+                    index = i;
+                }
+                break;
+            }
+        }
+
+        // If page is never used in future
+        if (j == num_pages) {
+            return i;
+        }
+    }
+
+    // If all pages will be used in future, return the one used farthest
+    return (index == -1) ? 0 : index;
+}
+
+// Optimal Page Replacement Algorithm
+void optimal(int* reference_string, int num_pages, int num_frames) {
+    int* frames = (int*)malloc(num_frames * sizeof(int));
+    int page_faults = 0;
+
+    // Initialize frames with -1 (indicating empty)
+    for (int i = 0; i < num_frames; i++) {
+        frames[i] = -1;
+    }
+
+    printf("\nOptimal Page Replacement Algorithm:\n");
+    printf("Reference String: ");
+    for (int i = 0; i < num_pages; i++) {
+        printf("%d ", reference_string[i]);
+    }
+    printf("\n\n");
+
+    for (int i = 0; i < num_pages; i++) {
+        printf("Page %d: ", reference_string[i]);
+
+        // Check if page already exists in frames
+        if (!isPagePresent(frames, num_frames, reference_string[i])) {
+            int free_frame = -1;
+
+            // Check if there's an empty frame
+            for (int j = 0; j < num_frames; j++) {
+                if (frames[j] == -1) {
+                    free_frame = j;
+                    break;
+                }
+            }
+
+            if (free_frame != -1) {
+                // If empty frame exists, use it
+                frames[free_frame] = reference_string[i];
+            } else {
+                // Find optimal page to replace
+                int replace_index = findOptimalPage(reference_string, frames, num_frames, num_pages, i);
+                frames[replace_index] = reference_string[i];
+            }
+
+            page_faults++;
+            printf("Page Fault! Frames: ");
+        } else {
+            printf("No Page Fault. Frames: ");
+        }
+
+        // Print current state of frames
+        for (int j = 0; j < num_frames; j++) {
+            if (frames[j] == -1) {
+                printf("[ ] ");
+            } else {
+                printf("[%d] ", frames[j]);
+            }
+        }
+        printf("\n");
+    }
+
+    printf("\nTotal Page Faults (Optimal): %d\n", page_faults);
+    free(frames);
+}
+
+int main() {
+    int num_pages, num_frames;
+
+    printf("Enter number of frames: ");
+    scanf("%d", &num_frames);
+
+    printf("Enter number of pages in reference string: ");
+    scanf("%d", &num_pages);
+
+    int* reference_string = (int*)malloc(num_pages * sizeof(int));
+
+    printf("Enter the reference string (page numbers):\n");
+    for (int i = 0; i < num_pages; i++) {
+        scanf("%d", &reference_string[i]);
+    }
+
+    // Run FIFO algorithm
+    fifo(reference_string, num_pages, num_frames);
+
+    // Run Optimal algorithm
+    optimal(reference_string, num_pages, num_frames);
+
+    free(reference_string);
+    return 0;
+}