Check if a number is positive or negative in Java (eugenp#12604)

sk1418 · web-flow · commit c56d1dc83dbd · 2022-08-20T21:46:14.000-05:00
* Check if a number is positive or negative in Java

* reformat single line if/else statements

* Check if a number is positive or negative in Java
diff --git a/core-java-modules/core-java-numbers-5/src/main/java/com/baeldung/positivenegative/PositiveOrNegative.java b/core-java-modules/core-java-numbers-5/src/main/java/com/baeldung/positivenegative/PositiveOrNegative.java
@@ -0,0 +1,38 @@
+package com.baeldung.positivenegative;
+
+public class PositiveOrNegative {
+    enum Result {
+        POSITIVE, NEGATIVE, ZERO
+    }
+
+    public static Result byOperator(Integer integer) {
+        if (integer > 0) {
+            return Result.POSITIVE;
+        } else if (integer < 0) {
+            return Result.NEGATIVE;
+        }
+        return Result.ZERO;
+    }
+
+    public static Result bySignum(Integer integer) {
+        int result = Integer.signum(integer);
+
+        if (result == 1) {
+            return Result.POSITIVE;
+        } else if (result == -1) {
+            return Result.NEGATIVE;
+        }
+        return Result.ZERO;
+    }
+
+    public static Result bySignum(Float floatNumber) {
+        float result = Math.signum(floatNumber);
+
+        if (result == 1.0f) {
+            return Result.POSITIVE;
+        } else if (result == -1.0f) {
+            return Result.NEGATIVE;
+        }
+        return Result.ZERO;
+    }
+}
diff --git a/core-java-modules/core-java-numbers-5/src/test/java/com/baeldung/positivenegative/PositiveOrNegativeUnitTest.java b/core-java-modules/core-java-numbers-5/src/test/java/com/baeldung/positivenegative/PositiveOrNegativeUnitTest.java
@@ -0,0 +1,29 @@
+package com.baeldung.positivenegative;
+
+import org.junit.jupiter.api.Test;
+
+import static com.baeldung.positivenegative.PositiveOrNegative.Result.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class PositiveOrNegativeUnitTest {
+    @Test
+    void givenIntegers_whenChkPositiveOrNegativeByOperator_thenReturnExpectedResult() {
+        assertEquals(POSITIVE, PositiveOrNegative.byOperator(42));
+        assertEquals(ZERO, PositiveOrNegative.byOperator(0));
+        assertEquals(NEGATIVE, PositiveOrNegative.byOperator(-700));
+    }
+
+    @Test
+    void givenIntegers_whenChkPositiveOrNegativeBySignum_thenReturnExpectedResult() {
+        assertEquals(POSITIVE, PositiveOrNegative.bySignum(42));
+        assertEquals(ZERO, PositiveOrNegative.bySignum(0));
+        assertEquals(NEGATIVE, PositiveOrNegative.bySignum(-700));
+    }
+
+    @Test
+    void givenFloats_whenChkPositiveOrNegativeBySignum_thenReturnExpectedResult() {
+        assertEquals(POSITIVE, PositiveOrNegative.bySignum(4.2f));
+        assertEquals(ZERO, PositiveOrNegative.bySignum(0f));
+        assertEquals(NEGATIVE, PositiveOrNegative.bySignum(-7.7f));
+    }
+}
