Added surface area of a cuboid

src/main/java/com/thealgorithms/maths/Area.java

@@ -35,6 +35,27 @@ public static double surfaceAreaCube(final double sideLength) {
         return 6 * sideLength * sideLength;
     }
 
+    /**
+     * Calculate the surface area of a cuboid.
+     *
+     * @param length length of the cuboid
+     * @param width width of the cuboid
+     * @param height height of the cuboid
+     * @return surface area of given cuboid
+     */
+    public static double surfaceAreaCuboid(final double length, double width, double height) {
+        if (length <= 0) {
+            throw new IllegalArgumentException("Length must be greater than 0");
+        }
+        if (width <= 0) {
+            throw new IllegalArgumentException("Width must be greater than 0");
+        }
+        if (height <= 0) {
+            throw new IllegalArgumentException("Height must be greater than 0");
+        }
+        return 2 * (length * width + length * height + width * height);
+    }
+
     /**
      * Calculate the surface area of a sphere.
      *

src/test/java/com/thealgorithms/maths/AreaTest.java

@@ -16,6 +16,11 @@ void testSurfaceAreaCube() {
         assertEquals(6.0, Area.surfaceAreaCube(1));
     }
 
+    @Test
+    void testSurfaceAreaCuboid() {
+        assertEquals(214.0, Area.surfaceAreaCuboid(5, 6, 7));
+    }
+
     @Test
     void testSurfaceAreaSphere() {
         assertEquals(12.566370614359172, Area.surfaceAreaSphere(1));
@@ -70,6 +75,12 @@ void surfaceAreaCone() {
     void testAllIllegalInput() {
         assertAll(()
                       -> assertThrows(IllegalArgumentException.class, () -> Area.surfaceAreaCube(0)),
+            ()
+                -> assertThrows(IllegalArgumentException.class, () -> Area.surfaceAreaCuboid(0, 1, 2)),
+            ()
+                -> assertThrows(IllegalArgumentException.class, () -> Area.surfaceAreaCuboid(1, 0, 2)),
+            ()
+                -> assertThrows(IllegalArgumentException.class, () -> Area.surfaceAreaCuboid(1, 2, 0)),
             ()
                 -> assertThrows(IllegalArgumentException.class, () -> Area.surfaceAreaSphere(0)),
             ()