对于大而准确的数字，我应该使用哪种数据类型？

Question

I'm making a simple Android calculator app which calculates percentages based on the numbers the users input. Usually it's within a reasonable value, so I used int. But I ran into problems with big numbers, and int automatically disposes of decimal values, so I'm trying to find an alternative. What data type should I use for big numbers, that is very accurate?

Answer 1

What data type should I use for large and accurate numbers?

I would use a BigDecimal per the Javadoc it is

Immutable, arbitrary-precision signed decimal numbers. A BigDecimal consists of an arbitrary precision integer unscaled value and a 32-bit integer scale .

For example,

BigDecimal a = new BigDecimal("1000");
BigDecimal b = new BigDecimal("0.001");
BigDecimal c = a.multiply(b);
System.out.println(c.toPlainString());