Best method to round up to the nearest 0.05 in java

Question

Consider that a tax of 10% is applicable on all items except food. Also, an additional tax of of 5 % is applicable on imported items.

If the cost of a music CD is

Answer 1

You can use long instead of double to use double you can do

double d = Math.round(d * 20) / 20.0; // round up to multiple of 0.05

to use long (as cents)

long l = (l + 3) / 5 * 5;

Although its often considered best practice to use int, long or BigDecimal most investment banks and funds use double because once you understand how to use them safely, they are simpler (than long) and faster (than BigDecimal) to use.