Calculating the Sum of Two Arrays Element by Element in Java (#14579)

* Create SumArraysUsingForLoop.java

* Update SumArraysUsingForLoop.java

* add sum arrays using for each loop and streams

* Create SumArraysUsingForLoopTest.java

* Add files via upload

* Update SumArraysUsingStreams.java

* Update and rename SumArraysUsingForEachTest.java to SumArraysUsingForEachUnitTest.java

* Rename SumArraysUsingForLoopTest.java to SumArraysUsingForLoopUnitTest.java

* Update and rename SumArraysUsingStreamsTest.java to SumArraysUsingStreamsUnitTest.java

* Update SumArraysUsingForEachUnitTest.java

* Update SumArraysUsingForLoopUnitTest.java

* Update SumArraysUsingForEachUnitTest.java

* Update SumArraysUsingStreamsUnitTest.java

core-java-modules/core-java-arrays-operations-advanced/src/main/java/com/baeldung/arraysums/SumArraysUsingForEach.java

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+package com.baeldung.arraysums;
+
+public class SumArraysUsingForEach {
+
+    public static int[] sumOfTwoArrays(int[] arr1, int[] arr2) {
+        int[] arr3 = new int[arr1.length];
+        int counter = 0;
+        for (int num1 : arr1) {
+            arr3[counter] = num1 + arr2[counter];
+            counter++;
+        }
+        return arr3;
+    }
+}

core-java-modules/core-java-arrays-operations-advanced/src/main/java/com/baeldung/arraysums/SumArraysUsingForLoop.java

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+package com.baeldung.arraysums;
+
+public class SumArraysUsingForLoop {
+
+    public static int[] sumOfTwoArrays(int[] arr1, int[] arr2) {
+        int[] arr3 = new int[arr1.length];
+        for (int i = 0; i < arr1.length; i++) {
+            arr3[i] = arr1[i] + arr2[i];
+        }
+        return arr3;
+    }
+}

core-java-modules/core-java-arrays-operations-advanced/src/main/java/com/baeldung/arraysums/SumArraysUsingStreams.java

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+package com.baeldung.arraysums;
+
+import java.util.Arrays;
+import java.util.stream.IntStream;
+
+public class SumArraysUsingStreams {
+
+    public static int[] sumOfTwoArrays(int[] arr1, int[] arr2) {
+        IntStream range = IntStream.range(0, Math.min(arr1.length, arr2.length));
+        IntStream stream3 = range.map(i -> arr1[i] + arr2[i]);
+        int[] arr3 = stream3.toArray();
+        return arr3;
+    }
+}

core-java-modules/core-java-arrays-operations-advanced/src/test/java/com/baeldung/arraysums/SumArraysUsingForEachUnitTest.java

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+package com.baeldung.arraysums;
+
+import com.baeldung.arraysums.SumArraysUsingForEach;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class SumArraysUsingForEachUnitTest {
+
+    @Test
+    public void sumOfTwoArraysUsingForEach_GivenTwoEqualSizedIntArrays_ReturnsCorrectSumArray() {
+        int[] arr1 = { 4, 5, 1, 6, 4, 15 };
+        int[] arr2 = { 3, 5, 6, 1, 9, 6 };
+        int[] expected = { 7, 10, 7, 7, 13, 21 };
+        assertArrayEquals(expected, SumArraysUsingForEach.sumOfTwoArrays(arr1, arr2));
+    }
+}

core-java-modules/core-java-arrays-operations-advanced/src/test/java/com/baeldung/arraysums/SumArraysUsingForLoopUnitTest.java

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+package com.baeldung.arraysums;
+
+import com.baeldung.arraysums.SumArraysUsingForLoop;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class SumArraysUsingForLoopUnitTest {
+
+    @Test
+    public void sumOfTwoArrays_GivenTwoEqualSizedIntArrays_ReturnsCorrectSumArray() {
+        int[] arr1 = {4, 5, 1, 6, 4, 15};
+        int[] arr2 = {3, 5, 6, 1, 9, 6};
+        int[] expected = {7, 10, 7, 7, 13, 21};
+        assertArrayEquals(expected, SumArraysUsingForLoop.sumOfTwoArrays(arr1, arr2));
+    }
+}

core-java-modules/core-java-arrays-operations-advanced/src/test/java/com/baeldung/arraysums/SumArraysUsingStreamsUnitTest.java

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+package com.baeldung.arraysums;
+
+import com.baeldung.arraysums.SumArraysUsingStreams;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class SumArraysUsingStreamsUnitTest {
+
+    @Test
+    public void sumOfTwoArraysUsingStreams_GivenTwoEqualSizedIntArrays_ReturnsCorrectSumArray() {
+        int[] arr1 = {4, 5, 1, 6, 4, 15};
+        int[] arr2 = {3, 5, 6, 1, 9, 6};
+        int[] expected = {7, 10, 7, 7, 13, 21};
+        assertArrayEquals(expected, SumArraysUsingStreams.sumOfTwoArrays(arr1, arr2));
+    }
+}