switch.cpp

#include <iostream>
using namespace std;

int main() {

    // ===================================================
    // 1. BASIC SWITCH STATEMENT
    // ===================================================
    int day = 4;

    cout << "=== 1. BASIC SWITCH STATEMENT ===" << endl;

    // The switch expression is evaluated once and compared with each case
    switch (day) {
        case 1:
            cout << "Monday" << endl;
            break; // Exits the switch block if matched
        case 2:
            cout << "Tuesday" << endl;
            break;
        case 3:
            cout << "Wednesday" << endl;
            break;
        case 4:
            cout << "Thursday" << endl; // Matched! Outputs "Thursday"
            break;
        case 5:
            cout << "Friday" << endl;
            break;
        default:
            cout << "Weekend" << endl; // Optional: Executes if no case matches
    }


    // ===================================================
    // 2. THE 'default' KEYWORD
    // ===================================================
    int unknownDay = 9;

    cout << "\n=== 2. THE DEFAULT KEYWORD ===" << endl;

    switch (unknownDay) {
        case 6:
            cout << "Saturday" << endl;
            break;
        case 7:
            cout << "Sunday" << endl;
            break;
        default:
            // Runs when 'unknownDay' doesn't match any case above
            cout << "Invalid day number!" << endl;
    }


    // ===================================================
    // 3. FALL-THROUGH BEHAVIOR (OMITTING 'break')
    // ===================================================
    int dayType = 6; // 6 = Saturday

    cout << "\n=== 3. FALL-THROUGH (MULTIPLE CASES) ===" << endl;

    switch (dayType) {
        // Grouping multiple cases together by omitting 'break'
        case 1:
        case 2:
        case 3:
        case 4:
        case 5:
            cout << "Weekday" << endl;
            break;
        case 6:
        case 7:
            cout << "Weekend!" << endl; // Matches case 6 and executes this
            break;
        default:
            cout << "Invalid day" << endl;
    }


    // ===================================================
    // 4. SWITCH WITH 'char' DATA TYPE
    // ===================================================
    char grade = 'B';

    cout << "\n=== 4. SWITCH WITH CHAR ===" << endl;

    // Switch also works with integral types like char, int, enum
    switch (grade) {
        case 'A':
            cout << "Excellent!" << endl;
            break;
        case 'B':
            cout << "Good job!" << endl; // Outputs "Good job!"
            break;
        case 'C':
            cout << "Fair" << endl;
            break;
        default:
            cout << "Needs improvement" << endl;
    }

    return 0;
}