Java int乘以浮点精度损失

Question

int totalSum = ids.length() * price;

length is int
price is float

I get this error:

error: possible loss of precision

how to multiply int by float correctly without losing precision?

Answer 1

Because you are getting result in int, which will ignore the values after decimal

try this

double totalSum = ids.length() * price;

Answer 2

Use BigDecimal.intvalue :

int i = new BigDecimal(ids.length).multiply(new BigDecimal(price)).intValue();

... or you can just cast the whole operation as int :

int totalSum = (int)(ids.length() * price);

Edit

As implied in comments, I'm making this explicit: casting as int or getting the int value will incur in a loss of precision.

Use Deepak's answer if you were just not sure about which type to pick (and accept his answer).

Answer 3

尝试这个：

float totalSum = (float) ids.length() * price;