Hello all as i remmber float maximum precision is 9 digits
but why in java its : only 5 ?
if i have :
float Val = Float.parseFloat(222.222222222);
when printing im geting : 222.22223
is there any way to keep the precision or to control it ?
say i like to see only 2 digits after the dot (.) ?
thanks
> Hello all as i remmber float maximum precision is 9
> digits
> but why in java its : only 5 ?
> if i have :
> > float Val = Float.parseFloat(222.222222222);
>
>
> when printing im geting : 222.22223
> is there any way to keep the precision or to control
> it ?
> say i like to see only 2 digits after the dot (.) ?
to get only 2 digits after the dot.
try
float Val = ((int)(Float.parseFloat(....) * 100) / 100.0);
> thanks
> Hello all as i remmber float maximum precision is 9
> digits but why in java its : only 5 ?
A floating point number uses a 24 bit binary mantissa. The 24th bit
is implicit. 24 bits make up ~ 16 million different numbers. This number
is about 6/7 decimal digits and that's all a float can do for you. Note
that you can multiply this mantissa with an 8 bit exponent, so you can do
fractions or rather large numbers too, but you still have about 6/7
significant decimals.
> is there any way to keep the precision or to control it ?
> say i like to see only 2 digits after the dot (.) ?
Have a look at the DecimalFormat class. Don't use the 'multiply
by 100 and divide by it' again trick because that doesn't work.
kind regards,
Jos
> > Hello all as i remmber float maximum precision is
> 9
> > digits but why in java its : only 5 ?
>
> A floating point number uses a 24 bit binary
> mantissa. The 24th bit
> is implicit. 24 bits make up ~ 16 million different
> numbers. This number
> is about 6/7 decimal digits and that's all a float
> can do for you. Note
> that you can multiply this mantissa with an 8 bit
> exponent, so you can do
> fractions or rather large numbers too, but you still
> have about 6/7
> significant decimals.
>
> > is there any way to keep the precision or to
> control it ?
> > say i like to see only 2 digits after the dot (.) ?
>
>
> Have a look at the DecimalFormat class. Don't
> use the 'multiply
> by 100 and divide by it' again trick because that
> doesn't work.
multiply by 100 and divide by 100 is used in apps where
the end user is shown a value in 2 decimal and the
value is further used in some calculations. if you keep
the original value which has higher precision then
there will be mismatch between the calculations.
>
> kind regards,
>
> Jos
> > Have a look at the DecimalFormat class. Don't use the 'multiply
> > by 100 and divide by it' again trick because that doesn't work.
> Multiply by 100 and divide by 100 is used in apps where the end user
> is shown a value in 2 decimal and the value is further used in some
> calculations. if you keep the original value which has higher precision
> then there will be mismatch between the calculations.
Run this and see for yourself:for (float f= 0.0f; f <= 1.0f; f+= 0.01f)
System.out.println("100*"+f+"/100.0= "+((int)(100*f))/100.0f);
kind regards,
Jos
}
Hello all well when i i did
//java.text.DecimalFormat dt = new java.text.DecimalFormat("####.00");
dt.setMinimumIntegerDigits(1);
dt.setMinimumFractionDigits(2);
String rr = dt.format(Val);
it worked fine , but now im trying to make it round up that is if i have
33.35 it will be 33.40 or if i have 22.226 it will be 22.23
i tryed this for example :
java.math.BigDecimal d = new java.math.BigDecimal("1115.36");
d = d.setScale(2, java.math.BigDecimal.ROUND_HALF_UP);
but the result remend the same 1115.36 and not 1115.36 as i want
what im doing wrong here ?
thanks for your help
> what i ment was
> if i have 1115.367
> i excpect it to be 1115.37 after rounding up
public static void main(String[] args) {
BigDecimal d = new java.math.BigDecimal("1115.367");
d = d.setScale(2, java.math.BigDecimal.ROUND_HALF_UP);
// I see 1115.37 printed
System.out.println(d);
// If all you want is a formatted string this does
// the job in 1.5
double dub = 1115.367;
System.out.printf("%.2f", dub);
}
See also String.format()
