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Compound operators...

Here you will find not so much a tutorial as a short discussion of the compound operators provided for your use by the people who built the Arduino language. Useful, but not rocket science. An easy "tutorial", for a change.

A "compound operator" is a shorthand way of accomplishing something which can be done by other means which merely involve more typing. The "other means" can, in some places, to some readers, be more transparent than the clever things you can do with compound operators.

We have looked at one, and sort of looked at another....

bTmp++;

... is the compound operator way of doing...

bTmp=bTmp+1;

This particular compound operator ("++") is, justifiably, commonly used in "for..." statements.

You should also know, although it doesn't matter to its use in "for..." statements, that it "returns the old value", whereas....

++bTmp;

... "returns the new value".

I suspect that means if you did....

intTmp=5;
Serial.println(intTmp++);

... you would get 5 in the serial monitor window, whereas

intTmp=5;
Serial.println(++intTmp);

....would give you 6 in the window. In both cases, if you subsequently did....

Serial.println(intTmp);

... you would get 6.

There are some other compound operator "shortcuts" of a similar nature...

x += y;   // equivalent to the expression x = x + y;
x -= y;   // equivalent to the expression x = x - y;
x *= y;   // equivalent to the expression x = x * y;
x /= y;   // equivalent to the expression x = x / y; 

Personally, I don't find the "pedestrian" versions, shown in the "equivalent" comment in each of the above too tedious... and I like the, to me, more clear representation afforded by, say....

x=x+y;

... but you may see "x += y; in other people's code, and now you know what it means, or you may disagree and think that the shortcut is clear and worthwhile. By all means use it, if you do!

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