NXC [BUG]: type casting int -> float not as expected

[HaWe]

hi,
... although I know about workarounds .... ,

calculating the following

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  float V=BatteryLevel()/1000;
  printf("Volt=%6.3f",V);

I always get results like
7.000 (BatteryLevel()=7312)
8.000 (BatteryLevel()=8294)
why don't I get values like 7.312 or 8.294 ?

As we got float as the result type I had expected that it should work automatically correctly casted to float.
what's faulty with the implicite type casting?
(and could we probably have explicite type casting soon?)

[spillerrec]

If BatteryLevel() returns an integer it will still do integer division even though you try to store it in a float. That is how it is supposed to work in C/C++. So use the workarounds until we have proper casting.

[HaWe]

As this is meant to be a bug report, using a workaround is not the issue (and finally we don't have explicite typecasting like in C/C++).

If I remember correctly, John wrote somewhere sometimes that NXC had implicite typecasting, so it should do implicitely a fp calculation depending on the target type... (that's at least what I expected from "implicite")

[afanofosc]

If either BatteryLevel() or 1000 were a float then you would get a float as the result. Since neither is a float then you get an integer result. Just add .0 to your 1000 so that is is a floating point type or multiply BatteryLevel() by 0.001 instead of dividing it by 1000.

This is working exactly as it should and is not a bug in NXC.

John Hansen

[HaWe]

Just add .0 to your 1000 so that is is a floating point type

That's exactly my workaround, or with variables I set
float fvar=int ivar; fvar/=1000
But the workarounds are not the point, I really thought implicite type casting means: it calculates depending on the target type implicitely automatically, just if I had written explicitely
V=(float)BatteryLevel()/1000

[afanofosc]

That would make NXC very not like C so it does not do that. NXC simply lets you cast things implicitly where some other languages require an explicit cast.

John Hansen

[HaWe]

That would make NXC very not like C

for heaven's sake, I would never wish THAT!
Then better have an additional (float)...^^

[muntoo]

Consider this:

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float x = (1234 / 1000);
// float x = (float) (1234 / 1000)

// 1234 / 1000 == 1

// float x = (float) (1);
// float x = 1.0;

The "implicit cast" is to the final result.

[HaWe]

muntoo,
what do you mean by that? can you pls explain?

[muntoo]

muntoo,
what do you mean by that? can you pls explain?

I mean that the expression (1234 / 1000) is always evaluated first. Then, it is assigned to the float. Since the value of that expression is 1, x is equal to 1.0.

The implicit cast is always around the whole expression:

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float x = float( /* expression */ );