Solve [Marwa] Accounts Information System - v1

main.cpp

#include<iostream>
#include <sstream>
#include<iomanip>

using namespace std;

string int_to_str(int i) // convert int to string
{
    stringstream s;
    s << i;
    return s.str();
}

struct account_query {
    int account_number;
    char firstName[10];
    char lastName[10];
    float total_Balance;
};
struct link {
    account_query data{};
    link *previous{nullptr};
    link *next{nullptr};
};

class Records {
private:
    link *latest{nullptr};
    static void print_account(link link){
        cout << "Account number: " << link.data.account_number
        << ", FN: " << link.data.firstName
        << ", LN: " << link.data.lastName
        << ", Balance = " << link.data.total_Balance
        << endl;
    }

    static int read_account_number(){
        int n;
        cout << "your number ";
        cin >> n;
        return n;
    }

    link* create_record(link* old_version = nullptr){
        int a;
        char f[10], l[10];
        float t;
        link *ctr = new link;

        if (old_version != nullptr){
            cout << "enter dash character - to ignore character based fields update" << endl;
            cout << "enter number -1 to ignore numeric based fields update" << endl;
        }

        // user should not be able to update account id.
        if (old_version == nullptr){
            while (true){
                cout << endl << "number is [write -1, to delegate the decision to the system]";
                cin >> a;
                if (a == -1){
                    if (latest == nullptr){
                        ctr->data.account_number = 1;
                    } else{
                        int i;
                        // to prevent duplication if user used mixed automatic and manual account number insertion
                        for (i = latest->data.account_number + 1; i < INT_MAX ; ++i) {
                            if (find_record(i) == nullptr){
                                break;
                            }
                        }
                        ctr->data.account_number = i;
                    }
                } else{
                    auto acc = find_record(a, true);
                    if (acc == nullptr){
                        ctr->data.account_number = a;
                        break;
                    }else{
                        cout << endl << "This number already exist" << endl;
                    }
                }
            }
        }

        cout <<"first name is : " << ((old_version != nullptr) ? old_version->data.firstName : "") << " ";
        cin >> f;
        strncpy_s(ctr->data.firstName, f, 10);

        cout <<"last name is "  << ((old_version != nullptr) ? old_version->data.lastName : "") << " ";
        cin >> l;
        strncpy_s(ctr->data.lastName, l, 10);

        cout <<"balance is " << ((old_version != nullptr) ? int_to_str(old_version->data.total_Balance) : "") << " ";

        cin >> t;
        ctr->data.total_Balance = t;
        return ctr;
    }

    link* find_record(int id, bool silent = false){
        link *read;
        read = latest;

        if (read == nullptr){
            if(!silent){
                cout << "not inserted" << endl;
            }
        }

        while (read != nullptr) {
            if (read->data.account_number == id){
                return read;
            }
            read = read->previous;
        }

        return nullptr;
    }

public:
    Records() { latest = nullptr; }

    void write_rec() {
        auto account = create_record();
        account->previous = latest;
        if (latest != nullptr){
            latest->next = account;
        }
        latest = account;
    }

    void read_rec() {
        int n = read_account_number();
        auto account = find_record(n);
        if (account == nullptr){
            cout << "Not Found";
        } else{
            print_account(*account);
        }
        cout << endl;
    }

    void update_rec() {
        int n = read_account_number();
        auto account = find_record(n);

        if (account == nullptr){
            cout << "Not Found";
        } else{
            auto new_account = create_record(account);
            if (!strcmp("-", new_account->data.firstName)){
                strncpy_s(account->data.firstName, new_account->data.firstName, 10);
            }
            if (!strcmp("-", new_account->data.lastName)){
                strncpy_s(account->data.lastName, new_account->data.lastName, 10);
            }
            if (new_account->data.account_number != -1){
                account->data.total_Balance = new_account->data.total_Balance;
            }
        }

        cout << endl;
    }

    void delete_rec() {
        int n = read_account_number();
        auto account = find_record(n);
        if (account == nullptr){
            cout << "Not Found";
        } else{
            if (account->previous != nullptr){
                account->previous->next = account->next;
            }
            if (account->next != nullptr){
                account->next->previous = account->previous;
            }

            delete account;
        }
        cout << endl;
    }

    void show_all(){
        auto ctr = latest;
        while (ctr != nullptr){
            print_account(*ctr);
            ctr = ctr->previous;
        }
    }
};

int main() {
    Records s1;
    int n;

    while (true) {
        cout << "***Accounts Information System***" << endl;
        cout << "Select one option from" << endl;
        cout << setw(6) << "1-->Add record to the system" << endl;
        cout << setw(6) << "2-->Show record from the system" << endl;
        cout << setw(6) << "3-->Update record from the system" << endl;
        cout << setw(6) << "4-->Delete record from the system" << endl;
        cout << setw(6) << "5-->Show All records from the system" << endl;
        cout << setw(6) << "6-->Quit the system" << endl;
        cout << "enter your choice:" << endl;
        cin >> n;

        switch (n) {
            case 1:
                s1.write_rec();
                break;
            case 2:
                s1.read_rec();
                break;
            case 3:
                s1.update_rec();
                break;
            case 4:
                s1.delete_rec();
                break;
            case 5:
                s1.show_all();
                break;;
            case 6:
                return 0;
            default:
                cout << "wrong number." << endl;
                break;
        }
    }
}