17. Log Message Timestamp

#include <iostream>
#include <string>
using namespace std;

// includeTimestamp default = false
void logMessage(const string& msg, bool includeTimestamp = false) {
    if (includeTimestamp) {
        cout << "[123456] " << msg;
    } else {
        cout << msg;
    }
}

int main() {
    int mode;
    string msg;
    cin >> mode >> msg;

    if (mode == 0) {
        logMessage(msg);            // default: no timestamp
    } else {
        logMessage(msg, true);      // timestamp enabled
    }

    return 0;
}

Explanation & Logic Summary:

• Default argument includeTimestamp = false makes the timestamp optional.
• Logging behavior changes based on the boolean flag.
• Adding optional timestamp support does not require a second overload.
• The message prints differently depending on whether timestamp is requested.

Firmware Relevance & Real-World Context:

• Logging systems in embedded firmware often support optional timestamps for debugging.
• Default arguments simplify API calls when timestamps are not needed.
• Mirrors real-world logging frameworks in RTOS, HAL, and diagnostic modules.
• Keeps the API minimal while still supporting richer output when required.