Runtime Logging Abstraction

#include <iostream>
using namespace std;

class OutputStream {
public:
    virtual void write(const char* msg) = 0;
    virtual ~OutputStream() = default;
};

class UartStream : public OutputStream {
public:
    void write(const char* msg) override {
        cout << "UART:" << msg << "\n";
    }
};

class SpiStream : public OutputStream {
public:
    void write(const char* msg) override {
        cout << "SPI:" << msg << "\n";
    }
};

OutputStream* selectStream(int type) {
    static UartStream uart;
    static SpiStream spi;

    if (type == 1) {
        return &uart;
    }
    if (type == 2) {
        return &spi;
    }
    return nullptr;
}

void logMessage(OutputStream* stream, const char* msg) {
    if (stream) {
        stream->write(msg);
    }
}

int main() {
    int transport;
    cin >> transport;

    int n;
    cin >> n;

    OutputStream* stream = selectStream(transport);

    for (int i = 0; i < n; ++i) {
        char msg[33];
        cin >> msg;
        logMessage(stream, msg);
    }

    return 0;
}