Delta_G Please read the last part first.
"how that huge number is represented and how 1.0 is represented"
You are wrong!
{
float magicNumber = 1.0;
....
float a = magicNumber;
char buffer[3];
dtostrf(a, 0, 1, buffer);
}
[1]- [0]
works perfectly fine but
{
float magicNumber = 1000.0;
....
float a =magicNumber;
char buffer[3];
dtostrf(a, 0, 1, buffer);
}
[1][0][0][0]- [0]
is a disaster. I hope you understand that.
Yes this could be avoided if we could know the exact value that comes out of magicNumber. But this magicNumber may come from another unit and if that unit fails to stay in range, you have to make sure the arduino side does not explode = writing in memory location that does not belong to the buffer.
"They're both going to be 32bit floating point which has about 6 or 7 digits of precision."
I do not know how is this even related. Yes all floats and doubles take 32 bit in Arduino but does it mean when they are printed by dtostrf with zero digit after the decimal point, the take same amount of memory? definitely not. (I hope you understand this too)
"When you call dtostrf you get to specify the precision so you get to specify how many digits get printed. "
You have probably read the link below but this is not how the arduino dtostrf work. You have probably read "prec determines the number of digits after the decimal sign" but in arduino it is "prec determines the number of digits after the decimal point". You can give it a shot if you do not believe me.
I think this is the reason why there is confusion here. I also checked the stdlib.h and the description is wrong.
I do not think the rest of the sprintf over head is not worth it nor needed.