diff --git a/CA3_me.c b/CA3_me.c
new file mode 100644
index 0000000..6507c32
--- /dev/null
+++ b/CA3_me.c
@@ -0,0 +1,486 @@
+#include<stdio.h>
+#include<stdlib.h>
+#include<string.h>
+
+#define FALSE 0
+#define TRUE 1
+#define MIN_ARRAY_LEN 2
+
+
+/*...................
+Author : Mahdy Mokhtari
+Student's ID : 810101515
+file : CA3
+Date : 1401 / 10 / 11
+....................*/
+
+
+typedef struct content content;
+typedef struct toti_user toti_user;
+
+struct content{
+    int post_id;
+    int like;
+    char* post;
+    //char** who_liked;
+    content* next;
+};
+
+struct toti_user {
+    content* my_content;
+    char* user_name;
+    char* password;
+    int num_of_posts;
+    toti_user* next;
+};
+
+
+char* command_getter(int*);
+char* part2_getter(int*);
+char* part3_getter(int*);
+int decoder (int*, int, char*, char*, char*, toti_user*, toti_user**, toti_user**);
+toti_user* signup(char*, char*, toti_user**, toti_user**, toti_user*);
+toti_user* login(char*, char*, toti_user**, toti_user**, toti_user*);
+toti_user* post(char*, char*, toti_user**, toti_user**, toti_user*);
+toti_user* like(char*, char*, toti_user**, toti_user**, toti_user*);
+toti_user* logout(toti_user**, toti_user**, toti_user*);
+toti_user* delete(char*, toti_user**, toti_user**, toti_user*);
+toti_user* info(toti_user**, toti_user**, toti_user*);
+toti_user* find_user(char*, toti_user**, toti_user**, toti_user*);
+void design(void);
+void print_in_file(toti_user*);
+
+int main() {
+    int flag_login = 0, counter = 0;
+    design();//////kamel kon
+    toti_user** tail_users;
+    tail_users = (toti_user**)malloc(sizeof(toti_user*));
+    *tail_users = (toti_user*)malloc(sizeof(toti_user));
+    if(tail_users == NULL) {
+        printf("coulnt malloc in main\n");
+    }
+    toti_user** node_cur_users;
+    node_cur_users = (toti_user**)malloc(sizeof(toti_user*));
+    *node_cur_users = *tail_users;
+    if(node_cur_users == NULL) {
+        printf("coulnt malloc in main\n");
+    }        
+    toti_user* head_users;
+    head_users = *tail_users;
+    head_users->next = NULL;
+    char *command, *part2, *part3;
+    while(TRUE) {
+        int num_last_part = 0, check_decoder = -1;
+        command = command_getter(&num_last_part); /*getting the command*/
+        if(num_last_part == 0) {  /*if we have more than one word we will put the second word in part2*/
+            part2 = part2_getter(&num_last_part);
+            if(num_last_part == 0) {  /*if we have more than 2 words we will get all the rest as a string in part3*/
+                part3 = part3_getter(&num_last_part);                
+            }
+        }
+        printf("command:%s  part2:%s  part3:%s  num_last_part:%d\n", command, part2, part3, num_last_part);
+        check_decoder = decoder(&flag_login, num_last_part, command, part2, part3, head_users, node_cur_users, tail_users);
+        if(check_decoder == FALSE) {
+            printf("not a correct command\n");
+        }
+        fflush(stdin);
+        if(counter != 0) {
+            if(num_last_part == 3) {
+                free(command), free(part2), free(part3);
+            }
+            else if(num_last_part == 2) {
+                free(command), free(part2);
+            }
+            else {
+                free(command);
+            }
+        }
+        counter++;
+        print_in_file(head_users);
+    }
+}
+
+void design(void) {
+    system("cls");
+    printf(".........................Hi, Wellcome to UT_TOTI...........................\n\nwrite your command...\n");
+}
+
+char* command_getter(int* num_last_part) {
+    char* command = (char*)malloc(sizeof(char) * MIN_ARRAY_LEN);
+    if(command == NULL) {
+        printf("couldnt malloc comand\n");
+        exit(0);
+    }
+    char temp;
+    int malloc_size = MIN_ARRAY_LEN; 
+    while(((temp = getchar()) != ' ') && (temp != '\n')) {
+        command = realloc(command, sizeof(char) * malloc_size);
+        if(command == NULL) {
+            printf("couldnt realloc part3\n");
+            exit(0);
+        }
+        command[malloc_size - 2] = temp;
+        malloc_size++;
+    }
+    if(temp == '\n') {
+        (*num_last_part) = 1;
+    }
+    command[malloc_size - 2] = '\0';
+    return command;
+}
+
+char* part2_getter(int* num_last_part) {
+    char* part2 = (char*)malloc(sizeof(char) * MIN_ARRAY_LEN);
+    char temp;
+    int malloc_size = MIN_ARRAY_LEN;
+    if(part2 == NULL) {
+        printf("couldnt malloc part2\n");
+        exit(0);
+    }
+    while(((temp = getchar()) != ' ') && (temp != '\n')) {
+        part2 = realloc(part2, sizeof(char) * malloc_size);
+        if(part2 == NULL) {
+            printf("couldnt realloc part3\n");
+            exit(0);
+        }
+        part2[malloc_size - 2] = temp;
+        malloc_size++;
+    }
+    if(temp == '\n') {
+        (*num_last_part) = 2;
+    }
+    part2[malloc_size - 2] = '\0';
+    return part2;
+}
+
+char* part3_getter(int* num_last_part) {
+    char* part3 = (char*)malloc(sizeof(char) * MIN_ARRAY_LEN);
+    char temp;
+    int malloc_size = MIN_ARRAY_LEN;
+    if(part3 == NULL) {
+        printf("couldnt malloc part3\n");
+        exit(0);
+    }
+    while((temp = getchar()) != '\n') {
+        part3 = realloc(part3, sizeof(char) * malloc_size);
+        if(part3 == NULL) {
+            printf("couldnt realloc part3\n");
+            exit(0);
+        }
+        part3[malloc_size - 2] = temp;
+        malloc_size++;
+    }
+    if(temp == '\n') {
+        (*num_last_part) = 3;
+    }
+    part3[malloc_size - 2] = '\0';
+    fflush(stdin);
+    return part3;
+}
+
+int decoder(int* flag_login, int num_last_part, char* command, char* part2, char* part3, toti_user* head_users, toti_user** node_cur_users, toti_user** tail_users) { /*finding witch command the user gave us and doing it*/
+    if(strcmp("signup", command) == 0) { 
+        if(*flag_login == 1 || num_last_part != 3) {
+            return FALSE;
+        }
+        else {
+            toti_user* check = head_users->next;
+            while (check != NULL) {
+                if(strcmp(check->user_name, part2) == 0) {
+                    printf("The username you picked is used\n");
+                    return FALSE;
+                }
+                check = check->next;
+            }
+            *flag_login = 0;
+            *node_cur_users = signup(part2, part3, tail_users, node_cur_users, head_users);
+        }
+    }
+    else if(strcmp("login", command) == 0) {
+        if(*flag_login == 1 || num_last_part != 3) {
+            return FALSE;
+        }
+        else {
+            *node_cur_users = login(part2, part3, tail_users, node_cur_users, head_users);
+            if(*node_cur_users == head_users) {
+                printf("The username or password is incorrect\n");
+                return FALSE;
+            }
+            else {
+                *flag_login = 1;
+            }
+        }
+    }
+    else if(strcmp("post", command) == 0) {
+        if((*flag_login) == 0 || num_last_part < 2) {
+            return FALSE;
+        }
+        else {
+            *flag_login = 1;
+            *node_cur_users = post(part2, part3, tail_users, node_cur_users, head_users);
+        }
+    }
+    else if(strcmp("info", command) == 0) {
+        if( num_last_part != 1) {
+            return FALSE;
+        }
+        else {
+            *flag_login = 1;
+            *node_cur_users = info(tail_users, node_cur_users, head_users);
+        }
+    }
+    else if(strcmp("like", command) == 0) {
+        if(*flag_login == 0 || num_last_part != 3) {
+            return FALSE;
+        }
+        else {
+            *flag_login = 1;
+            *node_cur_users = like(part2, part3, tail_users, node_cur_users, head_users);
+        }
+    }
+    else if(strcmp("logout", command) == 0) {
+        if(*flag_login == 0 || num_last_part != 1) {
+            return FALSE;
+        }
+        else {
+            *flag_login = 0;
+            *node_cur_users = logout(tail_users, node_cur_users, head_users);
+        }
+    }
+    else if(strcmp("delete", command) == 0) {
+        if(*flag_login == 0 || num_last_part != 2) {
+            return FALSE;
+        }
+        else {
+            *flag_login = 1;
+            *node_cur_users = delete(part2, tail_users, node_cur_users, head_users);
+        }        
+    }
+    else if(strcmp("find_user", command) == 0) {
+        if(*flag_login == 0 || num_last_part != 2) {
+            return FALSE;
+        }
+        else {
+            *flag_login = 1;
+            *node_cur_users = find_user(part2, tail_users, node_cur_users, head_users);
+        }
+    }
+    else {
+        return FALSE;
+    }
+    return TRUE;
+}  
+
+/*the return of all the bellow functions is the current node that we are logged in to or if we are not its the head of nodes*/
+
+toti_user* signup(char* part2, char* part3, toti_user** tail_users, toti_user** node_cur_users, toti_user* head_users) { 
+    int part2_size, part3_size;
+    (**tail_users).next = (toti_user*)malloc(sizeof(toti_user));
+    if((**tail_users).next == NULL) {
+        printf("couldnt malloc signup\n");
+    }/*writing the users information and saving it to signup*/
+    *tail_users = (**tail_users).next;
+    (**tail_users).next = NULL;
+    part2_size = strlen(part2);
+    part3_size = strlen(part3);
+    (**tail_users).user_name = (char*)malloc(sizeof(char) * part2_size);
+    (**tail_users).password = (char*)malloc(sizeof(char) * part3_size);
+    if((**tail_users).password == NULL || (**tail_users).user_name == NULL) {
+        printf("couldnt malloc in user or pass in signup\n");
+        exit(0);
+    }
+    strcpy((**tail_users).user_name, part2); 
+    strcpy((**tail_users).password, part3);
+    (**tail_users).num_of_posts = 0;
+    (**tail_users).my_content = (content*)malloc(sizeof(content)); 
+    ((**tail_users).my_content)->next = NULL;
+    if((**tail_users).my_content == NULL) {
+        printf("couldnt malloc my_content or who_liked in signup\n");
+        exit(0);
+    }
+    printf("signed up successefully\n");
+    return head_users;
+}
+
+toti_user* login(char* part2, char* part3, toti_user** tail_users, toti_user** node_cur_users, toti_user* head_users) {
+    toti_user *cur = head_users;
+    toti_user * prev = NULL;
+
+    while(cur != NULL) {/*finding the account that we want to signup in*/
+        if(strcmp(cur->user_name, part2) == 0 && strcmp(cur->password, part3) == 0) {
+            *node_cur_users = cur;
+            printf("logged in to: %s\n", (**node_cur_users).user_name);
+            return *node_cur_users;
+        }
+        prev = cur;
+        cur = cur->next;
+    }
+    return head_users;
+}
+
+toti_user* post(char* part2, char* part3, toti_user** tail_users, toti_user** node_cur_users, toti_user* head_users) {
+    content* cur = (**node_cur_users).my_content;      
+    content* prev = NULL;
+    int flag = 0;
+    if(cur->next == NULL) {
+        flag = 1;
+    }
+    while (cur != NULL) {  //finding the first empty node in the posts linked list
+        prev = cur;
+        cur = cur->next;
+    }/*adding the post to our content list*/
+    (**node_cur_users).num_of_posts++;
+    prev->next = (content*)malloc(sizeof(content));
+    (prev->next)->next = NULL;
+    (prev->next)->like = 0;
+    if (flag == 1) { //first post the it posted
+        (prev->next)->post_id = 1;
+    }
+    else {
+        (prev->next)->post_id = ((prev->post_id) + 1);
+    }
+    (prev->next)->post = (char*)malloc(sizeof(char) * (strlen(part2) + strlen(part3) + 1)); 
+    strcpy((prev->next)->post, part2);
+    strcat((prev->next)->post, " ");
+    strcat((prev->next)->post, part3);
+    return *node_cur_users;
+}
+
+toti_user* like(char* part2, char* part3, toti_user** tail_users, toti_user** node_cur_users, toti_user* head_users) {
+    toti_user* cur_user = head_users;
+    toti_user* prev_user = NULL;
+    int flag = 0; // this flag if it gets 1 means that we liked if 0 we didnt
+    while(cur_user != NULL) { // finding the user that has the post we want to like
+        if(strcmp(cur_user->user_name, part2) == 0) {
+            content* cur_content = cur_user->my_content;
+            content* prev_content = NULL;
+            while (cur_content != NULL) { // finding the post that we want to like
+                if(cur_content->post_id == atoi(part3)) {
+                    cur_content->like++;   //we havent strengthened repetitious likes
+                    flag = 1;
+                    break;
+                }
+                prev_content = cur_content;
+                cur_content = cur_content->next;
+            }
+            break;
+        }
+        prev_user = cur_user;
+        cur_user = cur_user->next;
+    }
+    if(flag == 1) {
+        printf("post liked successfuly\n");
+    }
+    else {
+        printf("post didnt got liked\n");
+    }
+    return *node_cur_users;
+}
+
+toti_user* info(toti_user** tail_users, toti_user** node_cur_users, toti_user* head_users) {
+    int flag = 0;
+    content* cur = ((**node_cur_users).my_content)->next;
+    content* prev = (**node_cur_users).my_content;
+    printf("Username: %s\n",(**node_cur_users).user_name);
+    printf("password: %s\n", (**node_cur_users).password);
+    while(cur != NULL) {
+        printf("post: %s\n", cur->post);
+        printf("post_id: %d\n", cur->post_id);
+        printf("like: %d\n", cur->like);
+        prev = cur;
+        cur = cur->next;
+        printf("\n");
+        flag = 1;
+    }
+    if(flag == 0) {
+        printf("you have no posts yet\n");
+    }
+    return *node_cur_users;
+}
+
+toti_user* logout(toti_user** tail, toti_user** node_cur_users, toti_user* head_users) {
+    *node_cur_users = head_users;
+    printf("You have logged out successfuly\n");
+    return *node_cur_users;
+}
+
+toti_user* delete(char* part2, toti_user** tail_users, toti_user** node_cur_users, toti_user* head_users) {
+    content* cur = (**node_cur_users).my_content;
+    content* prev = NULL;
+    int flag = 0;
+    while(cur != NULL) { 
+        if(cur->post_id == atoi(part2)) { //the post_id we want is found and deleted
+            flag = 1;
+            prev->next = cur->next;
+            free(cur->post);
+            free(cur);
+            break;
+        }
+        prev = cur;
+        cur = cur->next;
+    }
+    if(flag == 0) {
+        printf("You dont have that post_id\n");
+    }
+    else {
+        (**node_cur_users).num_of_posts--;
+        printf("post deleted successfuly\n");
+    }
+    return *node_cur_users;
+}
+
+toti_user* find_user(char* part2, toti_user** tail_users, toti_user** node_cur_users, toti_user* head_users) {
+    toti_user* cur_user = head_users;
+    toti_user* prev_user = NULL;
+    while(cur_user != NULL) {
+        if(strcmp(cur_user->user_name, part2) == 0) { //the username got matched and now we are printing its info
+            printf("Username: %s\n", cur_user->user_name);
+            int flag = 0;
+            content* cur = (cur_user->my_content)->next;
+            content* prev = cur_user->my_content;
+            while(cur != NULL) {
+                printf("post: %s\n", cur->post);
+                printf("post_id: %d\n", cur->post_id);
+                printf("like: %d\n", cur->like);
+                prev = cur;
+                cur = cur->next;
+                printf("\n");
+                flag = 1;
+            }
+            if(flag == 0) {
+            printf("you have no posts yet\n");
+            }
+            break;
+        }
+        prev_user = cur_user;
+        cur_user = cur_user->next;
+    }
+    return *node_cur_users;
+}
+
+void print_in_file(toti_user* head_users) {
+    FILE* account = fopen("C:\\Users\\MahdyBeast\\OneDrive\\Desktop\\programing\\C1\\.vscode\\CA3\\account.txt", "w");
+    FILE* post = fopen("C:\\Users\\MahdyBeast\\OneDrive\\Desktop\\programing\\C1\\.vscode\\CA3\\post.txt", "w");
+    if(post == NULL || account == NULL) {
+        printf("couldnt fopen\n");
+        exit(0);
+    }
+    toti_user* cur_user = head_users->next;
+    while(cur_user != NULL) {
+        int check_1 = fprintf(account, "%s %s %d\n", cur_user->user_name, cur_user->password, cur_user->num_of_posts);
+        if(check_1 < 0) {
+            printf("couldnt fprintf account.\n");
+        }
+        content* cur_content = (cur_user->my_content)->next; 
+        while(cur_content != NULL) {
+            int check_2 = fprintf(post, "%s %s %d\n", cur_content->post, cur_user->user_name, cur_content->like);
+            if(check_2 < 0) {
+                printf("couldnt fprintf account.\n");
+            }
+            cur_content = cur_content->next;
+        }
+        cur_user = cur_user->next;
+    }
+    fclose(account);
+    fclose(post);
+}
\ No newline at end of file
diff --git a/account.txt b/account.txt
new file mode 100644
index 0000000..d5c984a
--- /dev/null
+++ b/account.txt
@@ -0,0 +1,2 @@
+mahdy 123 2
+saman 112 0
diff --git a/post.txt b/post.txt
new file mode 100644
index 0000000..37e4ce9
--- /dev/null
+++ b/post.txt
@@ -0,0 +1,2 @@
+salam bar hamme mahdy 1
+ali is the bets mahdy 1