Khóa học C++ từ cơ bản đến nâng cao

switch (expression) {
    case value1:
        // Code thực thi khi expression == value1
        // ...
        break; // Rất quan trọng để thoát khỏi switch
    case value2:
        // Code thực thi khi expression == value2
        // ...
        break;
    // ... nhiều case khác ...
    default:
        // Code thực thi khi expression không khớp với bất kỳ case nào ở trên
        // ...
        break; // break ở default là tùy chọn, nhưng nên dùng để đồng nhất
}

#include <iostream>

int main() {
    cout << "--- MENU CHUONG TRINH ---" << endl;
    cout << "1. Them moi" << endl;
    cout << "2. Hien thi" << endl;
    cout << "3. Tim kiem" << endl;
    cout << "4. Thoat" << endl;
    cout << "-------------------------" << endl;
    cout << "Nhap lua chon cua ban: ";

    int luaChon;
    cin >> luaChon;

    switch (luaChon) {
        case 1:
            cout << "* Ban da chon: Them moi *" << endl;
            // Goi ham xu ly them moi du lieu
            break;
        case 2:
            cout << "* Ban da chon: Hien thi *" << endl;
            // Goi ham xu ly hien thi du lieu
            break;
        case 3:
            cout << "* Ban da chon: Tim kiem *" << endl;
            // Goi ham xu ly tim kiem du lieu
            break;
        case 4:
            cout << "* Ban da chon: Thoat chuong trinh *" << endl;
            // Thuc hien cac buoc thoat (luu du lieu truoc khi thoat...)
            break;
        default:
            cout << "* Lua chon khong hop le. Vui long nhap lai. *" << endl;
            // Thong bao loi cho nguoi dung
            break;
    }

    return 0;
}

#include <iostream>

int main() {
    int luaChon = 0; // Khoi tao gia tri de vao vong lap

    while (luaChon != 4) { // Vong lap tiep tuc cho den khi luaChon la 4
        cout << "\n--- MENU CHUONG TRINH ---" << endl;
        cout << "1. Them moi" << endl;
        cout << "2. Hien thi" << endl;
        cout << "3. Tim kiem" << endl;
        cout << "4. Thoat" << endl;
        cout << "-------------------------" << endl;
        cout << "Nhap lua chon cua ban: ";

        cin >> luaChon;

        switch (luaChon) {
            case 1:
                cout << "* Ban da chon: Them moi *" << endl;
                // Logic them moi
                break;
            case 2:
                cout << "* Ban da chon: Hien thi *" << endl;
                // Logic hien thi
                break;
            case 3:
                cout << "* Ban da chon: Tim kiem *" << endl;
                // Logic tim kiem
                break;
            case 4:
                cout << "* Ban da chon: Thoat chuong trinh *" << endl;
                // Logic thoat (vong lap se ket thuc sau khi case nay chay xong)
                break;
            default:
                cout << "* Lua chon khong hop le. Vui long nhap lai. *" << endl;
                // Logic xu ly loi
                break;
        }
    }

    cout << "Chuong trinh da ket thuc. Tam biet!" << endl;

    return 0;
}

#include <iostream>
#include <cctype> // De su dung tolower

int main() {
    char command;

    cout << "Nhap lenh ('A' them, 'D' xoa, 'Q' thoat): ";
    cin >> command;

    // Chuyen ky tu sang chu thuong de xu ly ca 'A' va 'a'
    command = tolower(command);

    switch (command) {
        case 'a':
            cout << "Lenh them moi duoc thuc thi." << endl;
            break;
        case 'd':
            cout << "Lenh xoa duoc thuc thi." << endl;
            break;
        case 'q':
            cout << "Dang thoat chuong trinh." << endl;
            break;
        default:
            cout << "Lenh khong hop le." << endl;
            break;
    }

    return 0;
}

#include <iostream>

int main() {
    int day;

    cout << "Nhap mot ngay trong tuan (1-7): ";
    cin >> day;

    switch (day) {
        case 1: // Chu nhat
        case 7: // Thu bay
            cout << "Day la ngay cuoi tuan! Rat tuyet!" << endl;
            break; // Break sau khi xu ly ca case 1 va case 7
        case 2: // Thu 2
        case 3: // Thu 3
        case 4: // Thu 4
        case 5: // Thu 5
        case 6: // Thu 6
            cout << "Day la ngay trong tuan. Co gang lam viec nao!" << endl;
            break; // Break sau khi xu ly tu case 2 den case 6
        default:
            cout << "Du lieu nhap khong hop le." << endl;
            break;
    }

    return 0;
}

#include <iostream>

int main() {
    int score;

    cout << "Nhap diem so (0-10): ";
    cin >> score;

    // Kiem tra diem so co hop le trong khoang 0-10 khong
    if (score < 0 || score > 10) {
        cout << "Diem khong hop le!" << endl;
    } else {
        // Chia diem cho 10 de nhom:
        // 0-9 -> 0
        // 10  -> 1
        // (Note: Voi thang diem 10, cach chia nay hoi don gian,
        // mot cach khac co the la chia theo khoang 0-4, 5, 6, 7, 8, 9, 10)
        // Hay thu mot cach phan loai theo muc diem pho bien hon:
        int category;
        if (score >= 9) {
            category = 4; // Gioi (9-10)
        } else if (score >= 7) {
            category = 3; // Kha (7-8)
        } else if (score >= 5) {
            category = 2; // Trung binh (5-6)
        } else if (score >= 3) {
             category = 1; // Yeu (3-4)
        }
        else {
            category = 0; // Kem (0-2)
        }


        switch (category) {
            case 4:
                cout << "Xep loai: Gioi" << endl;
                break;
            case 3:
                cout << "Xep loai: Kha" << endl;
                break;
            case 2:
                cout << "Xep loai: Trung binh" << endl;
                break;
             case 1:
                cout << "Xep loai: Yeu" << endl;
                break;
            case 0:
                cout << "Xep loai: Kem" << endl;
                break;
            // default o day se khong bao gio xay ra vi da kiem tra range truoc
        }
    }

    return 0;
}

#include <iostream>

// Dinh nghia mot enum class cho cac trang thai
enum class Status {
    Pending,    // 0 (theo mac dinh)
    Processing, // 1
    Completed,  // 2
    Failed      // 3
};

int main() {
    Status currentStatus = Status::Processing; // Gia su trang thai hien tai

    switch (currentStatus) {
        case Status::Pending:
            cout << "Trang thai: Dang cho xu ly." << endl;
            break;
        case Status::Processing:
            cout << "Trang thai: Dang xu ly." << endl;
            break;
        case Status::Completed:
            cout << "Trang thai: Hoan thanh." << endl;
            break;
        case Status::Failed:
            cout << "Trang thai: That bai." << endl;
            break;
        // Khong can default neu da xu ly het cac gia tri enum va khong co gia tri nao khac co the xay ra
    }

    // Vi du khac, nhap tu nguoi dung (can chuyen doi tu int sang enum)
    int userInput;
    cout << "Nhap trang thai (0: Pending, 1: Processing, 2: Completed, 3: Failed): ";
    cin >> userInput;

    // Chuyen doi int sang enum (can than voi input khong hop le)
    Status userStatus = static_cast<Status>(userInput);

    switch (userStatus) {
        case Status::Pending:
            cout << "Ban da nhap: Pending." << endl;
            break;
        case Status::Processing:
            cout << "Ban da nhap: Processing." << endl;
            break;
        case Status::Completed:
            cout << "Ban da nhap: Completed." << endl;
            break;
        case Status::Failed:
            cout << "Ban da nhap: Failed." << endl;
            break;
        default: // Nen co default khi input den tu ben ngoai co the khong hop le
             cout << "Input trang thai khong hop le." << endl;
            break;
    }


    return 0;
}