maybe this will work!

borland-tcpp-maybe.cpp

#include <iostream.h>
#include <string.h>
#include <fstream.h>

// Classes

class Todo{
  public:
    char content[200];
    char status;
    int _index;
};

class List {
  public:
    Todo list[20];

    char title[100];
    char tags[10][20];

    int _listIndex;     // Variable to count the filling of list
    int _tagIndex;      // Variable to count the filling of tags
    int _hasTags;

    List();                 // Asks for #title(required) and #tags(can be skipped).

    List(char Title[100]);  // Initialize the #list with #title

    void enter();           // Enter the info given by user

    void addTag(char Tag[20]); // Add the tag to Tags

    void setTitle(char Title[100]); // Set the Title given

    void view();            // View the list's #title #tags and #content

    void indexView();       // View the contents with the index

    void tagView();         // View only Title and tags

    void todoView(int);     // View the todo of index passed

    void tagIndexView();    // View the Title and Tags with the index

    void append();          // append a new ToDo in the #list

    void removeTodo(int);   // delete the list at index passed

    void removeTag(int);   // delete the tag at index passed

    void changeStatus(int index, char status); // Changes Status of the Item of #index to #status

    ~List() {}
};
List::List(){
    _listIndex = 0;
    _tagIndex = 0;
    _hasTags = 0;
}

List::List(char Title[100]) {
    _listIndex = 0;
    _tagIndex = 0;
    _hasTags = 0;

    strcpy(title, Title);
}

void List::enter(){
    cout << "Enter title for your list" << endl << " +> " ;
    cin.getline(title, sizeof(title));

    char choice[10];
    cout << "Do you want some tags? (yes/no)" << endl << " ?> " ;
    cin.getline(choice, sizeof(choice));

    if (!(strcmp(choice, "yes")*strcmp(choice, "y"))) {
        char tagTemp[20];

        cout << "Enter the tag one at a time" << endl << "\'d\' when done " << endl;
        cout << " +> " ;

        while (1) {
            cin.getline(tagTemp, sizeof(tagTemp));

            if (strcmp(tagTemp, "d") != 0) {
                addTag(tagTemp);
                cout << " +> " ;
            }

            else {
                break;
            }
        }

        _hasTags = 1;
    }

    // cout << "Has tags = " << _hasTags << endl;

}


void List::addTag(char Tag[20]) {
    strcpy(tags[_tagIndex++], Tag);
}

void List::setTitle(char Title[100]) {
    strcpy(title, Title);
}


void List::view() {
    cout << title << endl;
    cout << "============" << endl;

    if (_hasTags) {
        cout << "Tags : ";
        for (int i = 0; i < _tagIndex; i++) {
            cout << tags[i] << " ";
        }

        cout << endl << endl;
    }

    for (int i = 0; i < _listIndex; i++) {
        cout << "  [" << list[i].status << "]  ";
        cout << list[i].content << endl;
    }
}

void List::indexView() {
    cout << title << endl;
    cout << "============" << endl;

    if (_hasTags) {
        cout << "Tags : ";
        for (int i = 0; i < _tagIndex; i++) {
            cout << tags[i] << " ";
        }

        cout << endl << endl;
    }

    for (int i = 0; i < _listIndex; i++) {
        cout << " " << i << ". [" << list[i].status << "]  ";
        cout << list[i].content << endl;
    }
}

void List::tagView() {
    cout << title << endl;

    if (_hasTags) {
        cout << "Tags : ";
        for (int i = 0; i < _tagIndex; i++) {
            cout << tags[i] << " ";
        }

        cout << endl;
    }

}

void List::todoView(int index) {
    cout << index << ".  [" << list[index].status << "]  ";
    cout << list[index].content << endl;
}

void List::tagIndexView() {
    cout << title << endl;
    cout << "============" << endl;

    if (_hasTags) {
        cout << "Tags : ";
        for (int i = 0; i < _tagIndex; i++) {
            cout << tags[i] << " ";
        }

        cout << endl << endl;
    }

    else {
        cout << "No tags here." << endl;
    }
}

void List::append(){
    char Content[200];
    cout << "Enter the content of ToDo" << endl << " +> ";
    cin.getline(Content, sizeof(Content));

    strcpy(list[_listIndex].content, Content);

    list[_listIndex].status = ' ';
    list[_listIndex]._index = _listIndex;
    _listIndex++;
}

void List::removeTodo(int index) {
    for (int i = index; i < _listIndex; i++) {
        list[i] = list[i + 1];
    }
    _listIndex--;
}

void List::removeTag(int index) {
    for (int i = index; i < _tagIndex; i++) {
        strcpy(tags[i], tags[i + 1]);
    }
    _tagIndex--;
    if (_tagIndex == 0) {
        _hasTags = 0;
    }
}

void List::changeStatus(int index, char status){
    list[index].status = status;
}

void search(char term[], List arrayL[20]){
    int len = strlen(term);
    int found = 0;

    // Search in titles

    for (int i = 0; i < 20 ; i++) {
        int z = 0;
        found = 0;

        for (unsigned int k = 0; k < strlen(arrayL[i].title); k++) {
            if (tolower(term[z++]) == tolower(arrayL[i].title[k])) {
                found = 1;
                // cout << "Found title" << endl;
            }

            else {
                found = 0;
                z = 0;
            }

            if (z == len) {
                if (found) {
                    break;
                }
                z = 0;
            }
        }

        if (found) {
            cout << "Found in title, Index => " << i << endl << arrayL[i].title << endl;
        }
    }

    // Search in Tags

    for (int i = 0; i < 20 ; i++) {
        int z = 0;
        found = 0;
        for (int k = 0; k < arrayL[i]._tagIndex; k++) {
            z = 0;

            for (unsigned int c = 0; c < strlen(arrayL[i].tags[k]); c++) {

                if (tolower(term[z++]) == tolower(arrayL[i].tags[k][c])) {
                    found = 1;
                }

                else {
                    found = 0;
                    z = 0;
                }

                if (z == len) {

                    if (found) {
                        break;
                    }

                    z = 0;
                }
            }

            if (found) {
                cout << "Found in tag, Index => " << i << endl;
                arrayL[i].tagView();

                break;
            }
        }
    }

    // Search in Todos

    for (int i = 0; i < 20 ; i++) {
        int z = 0;
        found = 0;
        for (int k = 0; k < arrayL[i]._listIndex; k++) {
            z = 0;
            for (unsigned int c = 0; c < strlen(arrayL[i].list[k].content); c++) {

                if (tolower(term[z++]) == tolower(arrayL[i].list[k].content[c])) {
                    found = 1;
                }

                else {
                    found = 0;
                    z = 0;
                }

                if (z == len) {

                    if (found) {
                        break;
                    }

                    z = 0;
                }
            }

            if (found) {
                cout << "Found in ToDo, List Index => " << i << endl;

                arrayL[i].view();

                break;
            }
        }
    }
}
void Export(List Array[20], int _arrayLindex){
    char fname[40];

    cout << "Enter the Export file name " << endl  << " +> " ;
    cin.getline(fname, sizeof(fname));

    strcat(fname, ".tdexp");

    ofstream file;
    file.open(fname);

    for (int i = 0; i < _arrayLindex; i++) {
        file << Array[i].title << endl;
        file << "===============" << endl;

        file << "Tags : ";
        for (int j = 0; j < Array[i]._tagIndex; j++) {
            file << Array[i].tags[j] << " ";
        }
        file << endl;

        for (int k = 0; k < Array[i]._listIndex; k++) {
            file << " [" << Array[i].list[k].status << "] ";
            file << Array[i].list[k].content << endl;
        }

        file << endl;
    }

    cout << "File exported to : " << fname << " successfully :)" << endl;

    file.close();
}

List arrayL[20];
List currentL;

int _arrayLindex = 0;
int _currentLindex;
int isOpenL = 0; // For checking wether a list is open or not

char filename[20] = "data.tdx";

// Fxns Used

void    initiate();         // Initiate the data before user inteface
int     parse(char []);     // run the command entered by the users
void    stats();           // display stats of opened list
void    openL(int);         // open the list specified by index
void    displayL();         // display all the lists
int     confirm();          // ask for confirmation (y/n)
void    empty();            // remove data from the program & data-file
void    finish();           // save the data to the data-file

void initiate() {
    // Fxn to read data from external file int the array of Lists
    fstream file(filename, ios::in|ios::binary);
    List tempOb; // temperary object

    while (file.read((char*)&tempOb, sizeof(tempOb))) {
        arrayL[_arrayLindex++] = tempOb;
    }

    file.close();
}

int parse(char command[80]){
    // Fxn to Parse(execute) the command passed
    /// Here a crazy fun expression is used in if () {} to compare strings
    /// Since we wanted any of them to be zero, hence, they were multiplied
    /// to give zero. Mathematically it is quite accurate and syntactically
    /// beautiful.

    int success = 0; // to mark wether a command completed successfully

    if (!(strcmp(command, "new") * strcmp(command, "n"))) {
        // Create a new List
        arrayL[_arrayLindex++].enter();
        success = 1;
    }

    else if (!(strcmp(command, "stats") * strcmp(command, "stat"))) {
        // Display the stats
        stats();
        success = 1;
    }

    else if (!(strcmp(command, "open") * strcmp(command, "o"))) {
        // Open existing lists
        if (_arrayLindex) {
            if (isOpenL) {
                arrayL[_currentLindex] = currentL;
                finish();
            }

            int choice;
            cout << "Enter The No. of List to be opened" << endl;

            displayL();

            cout << " #> " ;
            cin >> choice;
            cin.ignore();

            while ( !(0 <= choice && choice < _arrayLindex) ) {
                cout << "Invalid choice choose again" << endl;
                cout << " #> " ;
                cin >> choice;
                cin.ignore();
            }

            openL(choice);

            isOpenL = 1;
        }

        else {
            cout << "No List found, create a new one with \'n\' or \'new\'" << endl;
        }

        success = 1;
    }

    else if (!(strcmp(command, "append") * strcmp(command, "a"))) {
        // Append a new Todo to the currently opened list
        if (isOpenL) {
            currentL.append();
        }

        else {
            cout << "No List is opened, Open a list first" << endl;
        }
        success = 1;
    }

    else if (!(strcmp(command, "mark") * strcmp(command, "m"))) {
        // Mark/(change status) a Todo with a given charater
        if (isOpenL) {
            int choice;
            currentL.indexView();

            cout << "Choose the Todo to mark : " << endl << " #> ";
            cin >> choice;

            while (choice >= currentL._listIndex || choice < 0) {
                cout << "Invalid Choice Try again" << endl << " #> ";
                cin >> choice;
            }

            char status;

            cout << "Enter The new Status" << endl << " +> " ;
            cin >> status;
            cin.ignore();

            currentL.changeStatus(choice, status);
        }

        else {
            cout << "No List is opened, Open a list first" << endl;
        }

        success = 1;
    }

    else if (!(strcmp(command, "addtag") * strcmp(command, "addt"))) {
        // Append a new Todo to the currently opened list
        if (isOpenL) {
            char newTag[40];

            cout << "Enter the New Tag " << endl << " +> ";
            cin.getline(newTag, sizeof(newTag));
            currentL.addTag(newTag);
        }

        else {
            cout << "No List is opened, Open a list first" << endl;
        }

        success = 1;
    }

    else if (!(strcmp(command, "view") * strcmp(command, "v"))) {
        // view todo's of the current list
        if (isOpenL) {
            currentL.view();
        }

        else {
            cout << "No List is opened, Open a list first" << endl;
        }

        success = 1;
    }

    else if (!(strcmp(command, "iview") * strcmp(command, "iv"))) {
        // view todo's of the current list with index
        if (isOpenL) {
            currentL.indexView();
        }

        else {
            cout << "No List is opened, Open a list first" << endl;
        }

        success = 1;
    }

    else if (!(strcmp(command, "search") * strcmp(command, "srch"))) {
        // Search the Database
        char searchTerm[40];

        cout << "Enter the search term " << endl << " +> ";
        cin.getline(searchTerm, sizeof(searchTerm));

        if (isOpenL) {
            arrayL[_currentLindex] = currentL;
        }

        search(searchTerm, arrayL);
        success = 1;
    }

    else if (!(strcmp(command, "save") * strcmp(command, "s"))) {
        // Save the data to the file
        if (isOpenL) {
            arrayL[_currentLindex] = currentL;
        }

        finish();
        success = 1;
    }

    else if (!(strcmp(command, "export") * strcmp(command, "exp"))) {
        // Export the data to a text file
        if (isOpenL) {
            arrayL[_currentLindex] = currentL;
        }

        Export(arrayL, _arrayLindex);

        success = 1;
    }

    else if (!(strcmp(command, "delete") * strcmp(command, "del"))) {
        // Delete Things

        char choice[10];
        cout << "What do you want to delete? (list/todo/tag)" << endl << " ?> ";
        cin.getline(choice, sizeof(choice));

        if (!(strcmp(choice, "list") * strcmp(choice, "List"))) {
            int index;

            cout << "Enter the Index of List to Delete " << endl;
            displayL();

            cout << " #> ";
            cin >> index;
            cin.ignore();
            cout << "Are you sure, This cannot be undone, This will delete the List ->" << endl;
            arrayL[index].view();

            if ( confirm() ) {
                for (int i = index; i < _arrayLindex - 1; i++) {
                    arrayL[i] = arrayL[i+1];
                }
                _arrayLindex--;
            }
        }

        else if (!(strcmp(choice, "todo") * strcmp(choice, "Todo") * strcmp(choice, "ToDo"))) {

            if (isOpenL) {
                int index;

                cout << "Enter the Index of Todo to Delete " << endl;
                currentL.indexView();

                cout << " #> ";
                cin >> index;
                cin.ignore();
                cout << "Are you sure, This cannot be undone, This will delete the ToDo ->" << endl;
                currentL.todoView(index);

                if ( confirm() ) {
                    currentL.removeTodo(index);
                }

                arrayL[_currentLindex] = currentL;  // To Help Improving Finalization
            }

            else {
                cout << "No List is opened, Open a list first" << endl;
            }
        }

        else if (!(strcmp(choice, "tag") * strcmp(choice, "tags") * strcmp(choice, "Tag"))) {

            if (isOpenL) {
                int index;

                cout << "Enter the Index of Tag to Delete " << endl;
                currentL.tagIndexView();

                cout << " #> " ;
                cin >> index;
                cin.ignore();
                cout << "Are you sure, This cannot be undone, This will delete the Tag ->" << endl;
                cout << currentL.tags[index] << endl;

                if ( confirm() ) {
                    currentL.removeTag(index);
                }

                arrayL[_currentLindex] = currentL;  // To Help Improving Finalization
            }

            else {
                cout << "No List is opened, Open a list first" << endl;
            }
        }

        finish();
        success = 1;
    }

    else if (!(strcmp(command, "qdelete") * strcmp(command, "qdel"))) {
        // Delete Todo of current list using index
        /// qdelete -> Quick Delete

        if (isOpenL) {
            int index;

            cout << "Enter the Index of List to Delete " << endl;
            currentL.indexView();

            cout << " #> " ;
            cin >> index;
            cin.ignore();
            cout << "Are you sure, This cannot be undone, This will delete ->" << endl;
            currentL.todoView(index);

            if ( confirm() ) {
                currentL.removeTodo(index);
            }

            arrayL[_currentLindex] = currentL;
        }

        else {
            cout << "No List is opened, Open a list first" << endl;
        }

        finish();
        success = 1;
    }

    else if (!(strcmp(command, "clear") * strcmp(command, "clr"))) {
        // Refresh the data file
        // XXX WARN XXX -> Strictly, Not to be used By users, Deletes all Data

        if ( confirm() ) {
            ofstream file(filename, ios::trunc|ios::binary|ios::out);

            file.write("", sizeof(arrayL));
            file.close();

            empty();
            initiate();
        }

        success = 1;
    }

    else if (!(strcmp(command, "quit") * strcmp(command, "q"))) {
        // exit the program after saving it to the file

        if ( confirm() ) {
            if (isOpenL) {
                arrayL[_currentLindex] = currentL;
            }

            finish();
            success = -1;
        }

        else {
            success = 1;
        }
    }

    else if (!(strcmp(command, "help") * strcmp(command, "-h"))) {
        // View help
        char line[80];
        ifstream helpfile("help.txt");

        while (!helpfile.eof()) {
            helpfile.getline(line, sizeof(line));
            cout << line << endl;
        }

        helpfile.close();

        success = 1;
    }

    return success;
}

void stats(){
    // Display wether a list is open or not
    if (isOpenL) {
        cout << "This List is open : " << currentL.title << endl;
        cout << "Total No. of todos : " << currentL._listIndex << endl;
    }

    else {
        cout << "No list is open" << endl;
    }

    cout << "Total lists = " << _arrayLindex << endl;
}

void openL(int index) {
    currentL = arrayL[index];
    _currentLindex = index;

    cout << "Opened : " << currentL.title << endl;
    currentL.view();
}

void displayL() {
    for (int i = 0; i < _arrayLindex; i++) {
        cout << i << ". " << arrayL[i].title << endl;
    }
}

int confirm() {
    // can be used as if( confirm() ) /// Improves yes/no prompts
    char confm[10];
    cout << "Enter \'yes\' to continue" << endl << " ?> " ;
    cin.getline(confm, sizeof(confm));

    if (!(strcmp(confm, "yes") * strcmp(confm, "y"))) {
        return 1;
    }

    else{
        return 0;
    }
}

void empty() {
    List tarrayL[20];
    memcpy(arrayL, tarrayL, sizeof(arrayL));
    _arrayLindex = 0;
    isOpenL = 0;
}

void finish() {
    // Write the changes back to file
    ofstream file (filename, ios::out);
    for (int i = 0; i < _arrayLindex; i++) {
        file.write((char*)&arrayL[i], sizeof(arrayL[i]));
    }

    file.close();
}

int main() {
    initiate();

    cout << "=== --- --> TodX  <-- --- ===" << endl;
    cout << "Welcome to TodX the ultimate Todo list" << endl;
    cout << "v1.03a = Borland DOS build, docs at -> http://todx.rtfd.io" << endl;

    char command[80];

    while (1) {
        cout << "\n *> ";
        cin.getline(command, sizeof(command));

        if (!cin) {
            cout << "Have a Great Day :)" << endl;
            break;
        }

        int result = parse(command);

        if(result > 0){
            continue;
        }

        else if (result == 0) {
            cout << "Command not found, try `help` for help" << endl;
        }

        else if (result == -1) {
            cout << "Data Saved, Have a Great Day :)" << endl;
            break;
        }

        else {
            cout << "Something went terribly wrong, we apologize :(" << endl;
        }
    }

    finish();

    return 0;
}

@sgrmshrsm7 compile it ASAP