Arduino: C++ Style

Here’s a simple tip that will make C coders cry and yell, but will definitely make C++ codes happy: how to implement C++ stream syntax for Arduino.

Based on the following tip from the Arduino Playground, I added a few things to make it more compatible with C++, so one can test a library on his computer, before running on the microcontroller:

static uint8_t base=0;
inline Print &operator <<(Print &obj, unsigned long arg)
{
    switch (base) {
        case HEX: obj.print(F("0x")); break;
        case BIN: obj.print(F("0b")); break;
    }
    obj.print(arg, (int)base);
    base = 0;
    return obj;
}
template<class T>
inline Print &operator <<(Print &obj, T arg) {
    obj.print(arg);
    return obj;
}
inline unsigned long hex(unsigned long arg) {
    base = HEX;
    return arg;
}
inline unsigned long bin(unsigned long arg) {
    base = BIN;
    return arg;
}

#define endl F("\n")
#define cout Serial

N.B.: I know there can be some improvement, mostly about the base variable, but at least that hack does the job of almost mimicking C++ like operators.

The idea is to be able to mimick the following syntax:

cout << "This is an address 0x" << hex << n << endl;

so it can work in both STL and Arduino frameworks. But at the time being all it does is

cout << "This is an address 0x" << hex(n) << endl;

It was a quick and dirty hack, and if you can suggest improvement on that, I’d be happy to hear! Don’t hesitate to comment and criticize that on Twitter!

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