i2c LCD shield; how to display numers (integers or long)

[fettlab]

I just got the LCD shield, the supplied examples, included in the library folder, work great on Arduino.
It is a nice shield, and I like the solution of a PIC handling the i2c (more charming than with a i2c expander like an Adafruit shield eg)

There is no example for displaying numbers in the library, only for characters.
I find out the library doesn't support numbers at all (like other LCD libraries do, but they won't work on this shield) , so you should do a number (integer and  unsigned long in my sketch) to character conversion in the Arduino sketch. I tried several ways to do this conversion, with commands like itoa, ltoa, sprint, String. But without success, I keep getting errors.
No need to explain I want to display numbers (from calculation, measurement, clock eg) and not only text.

Can someone supply me with a simple example sketch for displaying numbers (integers or long) on the LCD Shield

Another question:
If I don't want to use it as a shield, but just connect it through 4 (V, GND, SDA, SCL) wires with for instance a AtTiny85 (my favorite) , should I supply 3.3 V power , 5 V power or both?
Same Question for the GPIO, do the outputs generate 3.3 V or 5 V and are the inputs 5 V proof?

Thanks for replying

[MBR]

In C, if you can display a C-style string (zero-terminated array of characters), the C's sprintf() or snprintf() should work (prefer the second one, the first one is unsafe), with code like snprintf(output_buffer,OUTPUT_BUFFER_SIZE,"%d",number); (use "%ld" for longs). And if all this fails, you can allways convert the numbers "by hand" using repeated divisions and converting the remainders to ASCII numbers by adding 0x30.

[fettlab]

Thanks, snprintf() works great.
I found out I made a mistake in the buffer declaration, I wrote buffer(12) instead of buffer[12]. That's why ltoa and sprint() didn't work, it took me a long time to find, the error codes where misleading.