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BAEL-821 Added more test and updated round methods.

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This commit is contained in:
iaforek 2017-06-02 00:18:29 +01:00
parent fc58395ad4
commit c763d263ec
2 changed files with 55 additions and 4 deletions
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13
core-java/src/main/java/com/baeldung/maths/Round.java
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@ -17,7 +17,8 @@ public class Round {
DecimalFormat df = new DecimalFormat("###.###");
System.out.println(df.format(PI));
System.out.println(round(PI, 3));
System.out.println(roundOptional(PI, 3));
System.out.println(roundNotPrecise(PI, 3));
System.out.println(roundAvoid(PI, 3));
System.out.println(Precision.round(PI, 3));
System.out.println(DoubleRounder.round(PI, 3));
}
@ -25,12 +26,20 @@ public class Round {
public static double round(double value, int places) {
if (places < 0) throw new IllegalArgumentException();
BigDecimal bd = new BigDecimal(Double.toString(value));
bd = bd.setScale(places, RoundingMode.HALF_UP);
return bd.doubleValue();
}
public static double roundNotPrecise(double value, int places) {
if (places < 0) throw new IllegalArgumentException();
BigDecimal bd = new BigDecimal(value);
bd = bd.setScale(places, RoundingMode.HALF_UP);
return bd.doubleValue();
}
public static double roundOptional(double value, int places) {
public static double roundAvoid(double value, int places) {
double scale = Math.pow(10, places);
double rounded = Math.round(value * scale) / scale;
return rounded;

46
core-java/src/test/java/com/baeldung/maths/RoundTest.java
View File

@ -14,7 +14,8 @@ public class RoundTest {
@Test
public void givenDecimalNumber_roundToNDecimalPlaces_getExpectedResult() {
Assert.assertEquals(expected, Round.round(value, places), delta);
Assert.assertEquals(expected, Round.roundOptional(value, places), delta);
Assert.assertEquals(expected, Round.roundNotPrecise(value, places), delta);
Assert.assertEquals(expected, Round.roundAvoid(value, places), delta);
Assert.assertEquals(expected, Precision.round(value, places), delta);
Assert.assertEquals(expected, DoubleRounder.round(value, places), delta);
@ -22,7 +23,48 @@ public class RoundTest {
expected = 2.035d;
Assert.assertEquals(expected, Round.round(value, places), delta);
Assert.assertEquals(expected, Round.roundOptional(value, places), delta);
Assert.assertEquals(expected, Round.roundNotPrecise(value, places), delta);
Assert.assertEquals(expected, Round.roundAvoid(value, places), delta);
Assert.assertEquals(expected, Precision.round(value, places), delta);
Assert.assertEquals(expected, DoubleRounder.round(value, places), delta);
value = 1000.0d;
places = 17;
expected = 1000.0d;
Assert.assertEquals(expected, Round.round(value, places), delta);
Assert.assertEquals(expected, Round.roundNotPrecise(value, places), delta);
Assert.assertNotEquals(expected, Round.roundAvoid(value, places), delta); // Returns: 92.23372036854776 !
Assert.assertEquals(expected, Precision.round(value, places), delta);
Assert.assertEquals(expected, DoubleRounder.round(value, places), delta);
value = 256.025d;
places = 2;
expected = 256.03d;
Assert.assertEquals(expected, Round.round(value, places), delta);
Assert.assertNotEquals(expected, Round.roundNotPrecise(value, places), delta); // Returns: 256.02 !
Assert.assertNotEquals(expected, Round.roundAvoid(value, places), delta); // Returns: 256.02 !
Assert.assertEquals(expected, Precision.round(value, places), delta);
Assert.assertNotEquals(expected, DoubleRounder.round(value, places), delta); // Returns: 256.02 !
value = 260.775d;
places = 2;
expected = 260.78d;
Assert.assertEquals(expected, Round.round(value, places), delta);
Assert.assertNotEquals(expected, Round.roundNotPrecise(value, places), delta); // Returns: 260.77 !
Assert.assertNotEquals(expected, Round.roundAvoid(value, places), delta); // Returns: 260.77 !
Assert.assertEquals(expected, Precision.round(value, places), delta);
Assert.assertNotEquals(expected, DoubleRounder.round(value, places), delta); // Returns: 260.77 !
value = 90080070060.1d;
places = 9;
expected = 90080070060.1d;
Assert.assertEquals(expected, Round.round(value, places), delta);
Assert.assertEquals(expected, Round.roundNotPrecise(value, places), delta);
Assert.assertNotEquals(expected, Round.roundAvoid(value, places), delta); // Returns: 9.223372036854776E9 !
Assert.assertEquals(expected, Precision.round(value, places), delta);
Assert.assertEquals(expected, DoubleRounder.round(value, places), delta);
}