KwickCards Java
Math methods: watch the return type
ICSE JAVA · MATH CLASS
Math methods: watch the return type
| Method | Returns |
|---|---|
| round(double) | long |
| round(float) | int |
| ceil() | double |
| floor() | double |
| abs(int) | int |
ceil/floor give double: whole values print .0
Math.round(-2.5): is it -2 or -3? Many students get this wrong.
Math.round() adds 0.5 and takes the floor, so Math.round(-2.5) is -2. With a double argument it returns long, and with a float it returns int. Math.ceil(4.2) prints 5.0 and Math.floor(-4.5) prints -5.0, because both return double. Math.abs(-7) with an int argument returns the int 7.
In the exam, the return type decides whether you write the .0, and it is worth the mark.
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