sourcecode.c

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#include<string.h>
#include<windows.h>
#include<conio.h>



void changeColor(char* color);
void color_animation(char color_list[][3], int* time_list, int n);
void wlcScreen();
void seeTodo(int do_pause);
void CreateOrUpdateTodo();
void fixcount();
void DeleteTodo();
void EditTaskInTodo();
int listExists();
void chooseColor();
int mainMenu();
void inputPassword( char* password);
void login();



struct todo{
    int count;                          // Used to index one task of the ToDo List
    char data[50];                      // Used to store the task
    struct todo* next;                  // Used to link next node of task
};


static struct todo *start= NULL;        // Used to create the head node of the Linked List (First Node)



int main(){
     int choice;                         // store user choice
     wlcScreen();
     system("cls");
     login();
     system("cls");


    while(1){
        choice = mainMenu();
        switch(choice){
        case 1:
            seeTodo(1);
            break;
        case 2:
            CreateOrUpdateTodo();
            break;
        case 3:
            DeleteTodo();
            break;
        case 4:
            EditTaskInTodo();
            break;
        case 5:
            chooseColor();
            break;
        case 6:                            //for exit
            system("cls");
            exit(0);
        }
        
        system("cls");
        fflush(stdin);     // to clean input buffer


    }

    return 0;
}



int listExists(){
   // returns 1 if list already exist, otherwise it returns 0
    return (start != NULL);
}



void changeColor(char* color){

        /*
          Function Description : This function is used to change the color of the terminal
        */

        char finalcommand[100]="color ";        // Initial command string
        strcat(finalcommand,color);             // Concatenating color command string to the arguments
        system(finalcommand);                   // Sending the final command to the Terminal to change the color
    }



void color_animation(char color_list[][3], int* time_list, int n){

        /*
          Function Description : This function is used for color transition animation in welcome screen
        */


         int i =0;
         for (;i<n;i++){
                changeColor(color_list[i]);                                           // Used for changing color from the color list given in the code
                Sleep(*(time_list+i));                                                // Used for setting time delay between two color transition
          }
    }



void inputPassword( char* password){
/*
    Function Description: This function is used to hide the password with "*".
*/


 int p=0;
    do{
            password[p]=getch();

            if(password[p]!='\r')	      //"\r" is used to check when enter key is pressed.
	            printf("*");	      //It hides actual password with "*".

            p++;
    }while(password[p-1]!='\r');     //End of do while.

    password[p-1]='\0';		     //To end the password string by null "\0" charecter.

}



void login(){

/*
    Function Description: Function used for entering username, password and providing access to ToDo List
*/

    system("color f0");
	int a=0,i=0;                   // here "a" is used for counting the unsucessful attempts
    char uname[10];
    char pword[10];
    char user[10]="live";          // Username used in ToDoList
    char pass[10]="1234";          // Password used in ToDoList
    do
    {
        system("color f0");
        printf("\n\t\t\t  #--------------------------  LOGIN  --------------------------#  ");
        printf("\n\n\t\t\t                          Enter Username: ");
        scanf("%s", uname);
        printf("\n\t\t\t                          Enter Password: ");
		inputPassword(pword);                                              // Function used for hiding the user inputted password
        if(strcmp(uname,user)==0 && strcmp(pword,pass)==0)
        {
            printf("\n\n\n\t\t\t  >>                     Login successful                      <<");
            system("color f0");
            Sleep(700);
            system("cls");
            system("color f0");
            printf("\n\t\t\t\t  ---------------------------------------------------------  ");
            printf("\n\t\t\t\t  >>>>>>>>>>>>     WELCOME TO TODO LIST       <<<<<<<<<<<<  ");
            printf("\n\t\t\t\t  ---------------------------------------------------------  ");

            printf("\n\n\t\t\t\t                Initializing, please wait ");          // this is a cosmetic part to show a loading screen for some seconds
            for(i=1; i<=9; i++)
            {
                printf(".");
                Sleep(300);
            }
            printf("\n\n\t\t\t\t                Press any key to continue ...");
            getch();
            break;
        }
        else
        {
            system("color 0f");
            printf("\n\n\n\t\t\t  !!                     Login unsuccessful                    !!");
            printf("\n\n\n\t\t\t\t\t");
            a++;
            //getch();
            system("pause");
            system("cls");                       // clears the screen
        }
    }
	while(a<=2);
	{
        if (a>2)
        {
            system("color 0f");
            printf("\n\t\t\t  #--------------------------  ERROR  --------------------------# ");
            printf("\n\t\t\t  !!!                                                         !!! ");
            printf("\n\t\t\t  !!!               Todo list cannot be accesed.              !!! ");
            printf("\n\t\t\t  !!!                 Too many wrong attempts                 !!! ");
            printf("\n\t\t\t  !!!                  Re-execute the program                 !!! ");
            printf("\n\t\t\t  !!!                                                         !!! ");
            printf("\n\t\t\t  #-------------------------------------------------------------# \n");

            printf("\n\n\t\t\t\t\t  Press any key to EXIT...");
            getch();
            exit(1); // unsuccessful exit
        }
	}
    system("cls");
}



void wlcScreen(){
     /*
       Function Description : This function is used  prints the UI of the welcome screen
     */

    system("color f0");          // changes the colour to black and white.
    char c;
    system("cls");          // clears the screen."cls" is a pre defined console command.
    printf("\n\n\n\n      ");

    c=215;
    printf("\n\t\t\t\t\t         /-+-+-+-+-+-+-+-+-+-\\");          // all these printf statments are being used to make the UI for the welcome screen.
    printf("\n\t\t\t\t\t        /                     \\");          //the values which are being assigned to "char c" are ascii values.
    printf("\n\t\t\t\t\t       /                       \\");           // which are used to achieve certain symbols and designs for the welcome screen.
    printf("\n\t\t\t\t\t      /                         \\");
    printf("\n\n");


    // first line
    c=133;
    printf("\t\t\t\t\t%c%c%c%c%c%c",c,c,c,c,c,c);
    printf("\t\t\t\t %c%c%c%c%c%c",c,c,c,c,c,c);
    printf("\n\n\t       ");


    // second line

    c=42;
    for(int i=0; i<10; i++){
        printf("-%c",c);          // this prints star
    }

    c=126;
    for(int i=0; i<5; i++){
        printf("--%c",c);          //this prints a tilde
    }

    printf(" Welcome to ToDo List ");




    // tilde
    for(int i=0; i<4; i++){
        printf("%c--",c);          //this prints a tilde
    }

    printf("%c-",c);
                              // this also prints star
    c=42;
    for(int i=0; i<10; i++){
        printf("-%c",c);
    }
    printf("-\n");

    // third line
    c=157;
    printf("\n\t\t\t   ------ %c ------\t\t\t\t    ------ %c ------",c,c);


    // fourth line
    c=153;
    printf("\n\t\t\t\t\t\t\t   %c",c);


    // fifth line
    c=240;
    printf("\n\t\t\t\t\t\t\t ");
    for(int i=0; i<5; i++){
        printf("%c",c);
    }

    // sixth line
    c=194;
    printf("\n\t\t\t\t\t\t\t   %c",c);

    // seventh line
    printf("\n\t\t\t\t\t\t\t   |");

    // eighth line
    printf("\n\t\t\t\t\t\t\t   |");

    // ninth line
    printf("\n\t\t\t\t\t\t\t   |");

    // tenth line
    printf("\n\t\t\t\t\t\t\t   |");

    char color_list[8][3]= {"f1","f2","f4","f0","f4","f3","f2","f1"};
    int time_list[8]={100,100,100,100,100,100,100,100};

    color_animation(color_list,time_list, 8);



    //printf("\n\n\n\n\n");
    printf("\n\n\n\t\t\t\t\t      ");

    system("pause");          //this will pause the program and say "Press any key to continue . . .", after pressing any key.
}         //the control exits the wlcScreen function and comes to void choosecolor().



void chooseColor(){

        /*
             Function Description : chooseColor function let's  us deside in which color do we want the UI to be in.
        */


    system("cls");          // clears the screen.
    char colorInput[3];
    printf("\n\n\n\n\n\n\n\n\n\n\n                                            WHICH COLOR YOU WANT?\n");
    printf("%80s","Type Background letter folowed by Font letter.\n");
    printf("%s","                                            0 = Black       8 = Gray\n");
    printf("%s","                                            1 = Blue        9 = Light Blue\n");          //printing all the possible color's we can use in C language cmd.
    printf("%s","                                            2 = Green       A = Light Green\n");
    printf("%s","                                            3 = Aqua        B = Light Aqua\n");
    printf("%s","                                            4 = Red         C = Light Red\n");
    printf("%s","                                            5 = Purple      D = Light Purple\n");
    printf("%s","                                            6 = Yellow      E = Light Yellow\n");
    printf("%s","                                            7 = White       F = Bright White\n");
    printf("%s","                                                           ");
    scanf("%s",colorInput);                                                                                //taking input from the user.

    if ( (colorInput[0] >= '0' && colorInput[0] <= '9') || (colorInput[0] >= 'A' && colorInput[0] <= 'F') || (colorInput[0] >= 'a' && colorInput[0] <= 'f')){
    if ( (colorInput[1] >= '0' && colorInput[1] <= '9') || (colorInput[1] >= 'A' && colorInput[1] <= 'F') || (colorInput[1] >= 'a' && colorInput[1] <= 'f')){
                changeColor(colorInput);
        }                                                  //cheching if the user has given a valid Input.
    }
    else {
        printf("                                            Invalid Response.\n");           //if the given input is not in the specified format, this else statment gets executed.
        printf("                                            Try Again in 3 seconds.\n");    // and prints Invalid Response, and Try again in 3 Seconds.
        Sleep(3000);                                                                       //this sleep(3000); function stops the program for 3000 milliseconds.
        chooseColor();                                                                    //Again the chooseColor(); function is called so the user can have another try.
     }


}



int mainMenu(){//sai

    /*
         Function Description : This function is used  prints Menu of the Todo list and returns a choice entered by user
     */

    int choice;


    system("cls");          //clears the screen.
    //
    struct tm* ptr;
    time_t t;
    t = time(NULL);          //these five lines of code take the time as an input from windows.h(header file).
    ptr = localtime(&t);    //And prints it on the main menu.
    printf("\n\n\n\n\n\n\n\n                                                 %s", asctime(ptr));
    printf("\n\n");
    printf("\n\t\t\t\t\t\t 1. See your ToDo List. \n");             //printing all the contents of the main menu.
    if (listExists()){                                              // here in this if else stament if we have alredy created a todolist.
        printf("\n\t\t\t\t\t\t 2. Update your ToDo List. \n");      //listExists(); fuctions returns "1" and if statment will be executed.
    }                                                               //And prints update your todolist, in case if there is no todolist else stament get's executed.
    else {                                                          //which prints create your todollist.
        printf("\n\t\t\t\t\t\t 2. Create your ToDo List. \n");
    }
    printf("\n\t\t\t\t\t\t 3. Delete your ToDo List. \n");
    printf("\n\t\t\t\t\t\t 4. Edit task in your ToDo List. \n");
    printf("\n\t\t\t\t\t\t 5. Change Font Color \n");
    printf("\n\t\t\t\t\t\t 6. Exit ");
    printf("\n\t\t\t\t\t\t");
    printf("\n\t\t\t\t\t\t");
    printf("\n\t\t\t\t\t\t Enter your choice \n\t\t\t\t\t\t --> ");
    fflush(stdin);     // to clean input buffer
    scanf("%d",&choice);          //takes input from the user and returns to void main();
    return choice;
}

void seeTodo(int do_pause){
    /*
       Function Description : This function is used to print the todo list along with its index number
       Also if do_pause is not 0 then it pause the seeTodo function. this is done to use seeTodo multiple places.
     */
    system("cls");
    struct todo *temp;
    temp = start;
    if(start == NULL)              // checks if the list is empty
    {
        printf("\n\t\t\t\t\t\t Empty list");
    }
    else
    {
        while(temp != NULL)        //Traversing e whole list
        {
            printf("\n\t\t\t\t\t\t %d . ",temp->count);   //to display index of the Task
            puts(temp->data);      // to display / print the Task of the Node of the todo list
            fflush(stdin);         // to clear the input buffer
            temp = (temp->next);   // storing next node in temp variable
        }
    }
    printf("\n\t\t\t\t\t\t");
    if (do_pause)
    system("pause");

}

struct todo* todoNodeCpy (struct todo* todoNode1 , struct todo* todoNode2){

     /*
        Function Description : This function is used to copy data of Node 2 to data of Node 1
     */
    strcpy (todoNode1->data, todoNode2->data);
    return todoNode1;
}

struct todo* creatNewNode(){
     /*
       Function Description : This function is used for dynamic memory allocation for a Node.
     */
    struct todo* newNode = (struct todo*) malloc(1*sizeof(struct todo));
    newNode->next = NULL; // so that last node next pointer is always null. property of linked list to work
    return newNode;
}

struct todo* addNode(struct todo* todoNode){

     /*
         Function Description : This function is used for adding a new node to the given node
     */
    struct todo* creatNewNode();

    todoNode->next = creatNewNode();
    return todoNode->next;
}

struct todo* addNextNode (struct todo* todoNode, struct todo element){

     /*
         Function Description : This function is used for adding a new node to the last of the linked list
     */

    struct todo* getLastNode(struct todo* todoNode);
    struct todo* addNode(struct todo* todoNode);
    struct todo* todoNodeCpy (struct todo* todoNode1 , struct todo* todoNode2);

    struct todo* lastNode = getLastNode(todoNode);  // used to get the last node of the list.
    int lastNodeCountValue = lastNode->count;       // storing last index value
    lastNode = addNode(lastNode);                   // adding a new Node at the last
    todoNodeCpy(lastNode,&element);                 // copying the argument value to the last node which is just made
    lastNode->count = ++lastNodeCountValue;         // setting its pindex value one more than the second last node index
    return lastNode;
}

struct todo* getNextNode(struct todo* todoNode) {
     /*
         Function Description : This function is used to get Next node of the given node
     */

    return todoNode->next;
}

struct todo* getLastNode(struct todo* todoNode){
     /*
        Function Description : This function is used to get last node Last node of the given linked list.
        its made to work recursivly
     */

    struct todo* getNextNode(struct todo* todoNode);
    struct todo* nextNode = getNextNode(todoNode); // to get next node
    if (nextNode == NULL) return todoNode; // if its the last node then its nextNode pointer should point to null,
    else return getLastNode(nextNode); //otherwise it should check the next node
    }

void CreateOrUpdateTodo(){

     /*
         Function Description : This function is used to create a List (when the list is empty), or add a new node at last of the list if the list already exist
     */
    struct todo* creatNewNode();
    struct todo* addNextNode (struct todo* todoNode, struct todo element);

    char a[500];      //to store response of user choice to add new task or not
    system("cls");

    while(1){
        printf("\n\t\t\t\t\t\t Want to add? y/n \n\t\t\t\t\t\t -->");
        fflush(stdin);     // to clean input buffer
        scanf("%s",a);

        if(a[0] =='y' && a[1] == '\0')    // if user input y, yes to add new task to linked list
        {
            if(start == NULL)             // if list is empty
            {
                start = creatNewNode();   // made a new node
                start->count = 1;         // to make index of head node as 1
                printf("\n\t\t\t\t\t\t Write 1st list here \n\t\t\t\t\t\t --> ");
                fflush(stdin);            // to clear input buffer
                gets(start->data);        // input new task data into the list


            }
            else
            {


                printf("\n\t\t\t\t\t\t Write another list here \n\t\t\t\t\t\t --> ");
                fflush(stdin);            //to clear input buffer
                struct todo tempNode;
                gets(tempNode.data);      //to store input of task to a temp node
                addNextNode (start,tempNode);    // add this temp node to last of link list
            }
        }
        if(a[0]=='n'&& a[1]=='\0')        // if user input is n, not to add new task to list
        {
            break;
        }
    }


}

void fixcount(){
     /*
        Function Description : once we delete the node, all index should be done again, thats what this function does.
     */

    struct todo *ptr; // temporary variable to store menu of start (HEAD) static variable
    int i=1;
    ptr = start;
    while(ptr != NULL) // the the end of the linked list
    {
        ptr->count = i; // assign the coounter variable i to count variable of the struct
        i++;
        ptr= ptr->next; // to get next node of the linked list
    }
}

void DeleteTodo(){

     /*
        Function Description :  This function is used to delete/remove a task (Node) from the Todo, by taking input of the index number of that task
     */

    system("cls");
    if(start != NULL){         //checks that linked list is not null
    seeTodo(0);                // display the current list to the user along with index, so that user can easily understand what has to be deleted.
    int a;                     // store index location to be deleted.
    int flagFound = 0;         // store if we can actually successful in deleting the Task (Node)
    printf("\n\t\t\t\t\t\t Enter the Index you want to delete \n\t\t\t\t\t\t --> ");
    scanf("%d",&a);

    if (a==1){                 // if user wants to delete Head Node, that is treated differently compared to other nodes

         struct todo* NodeToDelete = start;     // store thet Head that has to be deleted node to a temporary variable
         start = start -> next;                 // change pointer location of the Head node to next node
         free(NodeToDelete);                    // delete the old head node
         flagFound=1;                           // if the node deleted successfully
    }
    else {                    // if user wants to delete other Node,
    struct todo* loopCounter = start;           //store node pointer to move to whole list
    while(loopCounter -> next != NULL)
    {

        if(loopCounter->next->count == a)       // if list index value matches the index to deleted givin by the user
        {
            struct todo* NodeToDelete = loopCounter->next;     // swaping to save next node, and link to previous node, before deleting
            loopCounter->next = NodeToDelete->next;
            free(NodeToDelete);                                // delete the node
            flagFound =1;                                      // if the node deleted successfully
            break;
        }

        loopCounter = loopCounter->next;

    }
    }
    if (!flagFound){                                           // if the index is not found in the list
        printf("\n\t\t\t\t\t\t Index Not Found. \n\t\t\t\t\t\t");
        system ("pause");
    }
    else{
        fixcount();                                            // after deleting the node , fixing the index of all elements of the list, cus one element is deleted, it changed the indexing
    }
}
    else {
            printf("\n\t\t\t\t\t\t Cannot delete as list is empty.\n\t\t\t\t\t\t"); // if the list is empty
            system ("pause");
    }
}


void EditTaskInTodo(){

     /*
        Function Description :  This function is used to edit a task (Node) from the Todo, by taking input of the index number of that task 
     */

    system("cls");
    if(start != NULL){         //checks that linked list is not null
    seeTodo(0);                // display the current list to the user along with index, so that user can easily understand what has to be edited.
    int a;                     // store index location to be edited.
    int flagFound = 0;         // store if we can actually successful in editing the Task (Node)
    printf("\n\t\t\t\t\t\t Enter the Index you want to edit\n\t\t\t\t\t\t --> ");
    scanf("%d",&a);

    struct todo* loopCounter = start;           //store node pointer to move to whole list
    while(loopCounter != NULL)
    {

        if(loopCounter->count == a)       // if list index value matches the index to edited givin by the user
        {

             flagFound =1;                                      // if the node edited successfully
             printf("\n\t\t\t\t\t\t Enter New Task\n\t\t\t\t\t\t --> ");
             fflush(stdin);            // to clear input buffer
             gets(loopCounter->data);
             break;
        }

        loopCounter = loopCounter->next;

    }

    if (!flagFound){                                           // if the index is not found in the list
        printf("\n\t\t\t\t\t\t Index Not Found. \n\t\t\t\t\t\t");
        system ("pause");
    }
    else{
        fixcount();                                            // after edited the node , fixing the index of all elements of the list
    }
}
    else {
            printf("\n\t\t\t\t\t\t Cannot edit as list is empty.\n\t\t\t\t\t\t"); // if the list is empty
            system ("pause");
    }

}