問題文
A summary screen needs the whole number that is nearest to a double value, and the value can be negative. Which statement about Math.round is accurate?
選択肢
- It drops the fraction in the same way as a cast to long does, so an argument of 2.7 comes back as 2 instead of as 3
- It returns a double when the argument is a double, so the result has to be rounded a second time before it can be stored in a long
- It adds one half to the argument and then takes the floor, so an argument of minus 2.5 comes back as minus 2 rather than as minus 3
- It moves a value away from zero whenever the fraction is exactly one half, so minus 2.5 comes back as minus 3