diff --git a/src/KMeans/Cluster.php b/src/KMeans/Cluster.php
index 68e700f..bfd2d71 100644
--- a/src/KMeans/Cluster.php
+++ b/src/KMeans/Cluster.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * This file is part of PHP K-Means
  *
@@ -33,7 +34,7 @@ class Cluster extends Point implements \IteratorAggregate, \Countable
     public function __construct(Space $space, array $coordinates)
     {
         parent::__construct($space, $coordinates);
-        $this->points = new \SplObjectStorage;
+        $this->points = new \SplObjectStorage();
     }
 
     public function toArray(): array
@@ -84,12 +85,12 @@ public function updateCentroid(): void
         $centroid = $this->space->newPoint(array_fill(0, $this->dimention, 0));
 
         foreach ($this->points as $point) {
-            for ($n=0; $n<$this->dimention; $n++) {
+            for ($n = 0; $n < $this->dimention; $n++) {
                 $centroid->coordinates[$n] += $point->coordinates[$n];
             }
         }
 
-        for ($n=0; $n<$this->dimention; $n++) {
+        for ($n = 0; $n < $this->dimention; $n++) {
             $this->coordinates[$n] = $centroid->coordinates[$n] / $count;
         }
     }
diff --git a/src/KMeans/Point.php b/src/KMeans/Point.php
index 8621fee..6d6e682 100644
--- a/src/KMeans/Point.php
+++ b/src/KMeans/Point.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * This file is part of PHP K-Means
  *
@@ -53,7 +54,7 @@ public function getDistanceWith(self $point, bool $precise = true): float
         }
 
         $distance = 0;
-        for ($n=0; $n<$this->dimention; $n++) {
+        for ($n = 0; $n < $this->dimention; $n++) {
             $difference = $this->coordinates[$n] - $point->coordinates[$n];
             $distance  += $difference * $difference;
         }
diff --git a/src/KMeans/Space.php b/src/KMeans/Space.php
index 73e001e..b7ac42e 100644
--- a/src/KMeans/Space.php
+++ b/src/KMeans/Space.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * This file is part of PHP K-Means
  *
@@ -95,7 +96,7 @@ public function getBoundaries(): array
         $max = $this->newPoint(array_fill(0, $this->dimention, null));
 
         foreach ($this as $point) {
-            for ($n=0; $n < $this->dimention; $n++) {
+            for ($n = 0; $n < $this->dimention; $n++) {
                 if ($min[$n] === null || $min[$n] > $point[$n]) {
                     $min[$n] = $point[$n];
                 }
@@ -114,7 +115,7 @@ public function getRandomPoint(Point $min, Point $max): Point
         $point = $this->newPoint(array_fill(0, $this->dimention, null));
         $rng = static::$rng;
 
-        for ($n=0; $n < $this->dimention; $n++) {
+        for ($n = 0; $n < $this->dimention; $n++) {
             $point[$n] = $rng($min[$n], $max[$n]);
         }
 
@@ -154,7 +155,7 @@ protected function initializeClusters(int $nbClusters): array
         list($min, $max) = $this->getBoundaries();
 
         // initialize N clusters with a random point within space boundaries
-        for ($n=0; $n<$nbClusters; $n++) {
+        for ($n = 0; $n < $nbClusters; $n++) {
             $clusters[] = new Cluster($this, $this->getRandomPoint($min, $max)->getCoordinates());
         }
 
@@ -169,8 +170,8 @@ protected function iterate(array $clusters): bool
         $continue = false;
 
         // migration storages
-        $attach = new \SplObjectStorage;
-        $detach = new \SplObjectStorage;
+        $attach = new \SplObjectStorage();
+        $detach = new \SplObjectStorage();
 
         // calculate proximity amongst points and clusters
         foreach ($clusters as $cluster) {
@@ -181,11 +182,11 @@ protected function iterate(array $clusters): bool
                 // move the point from its old cluster to its closest
                 if ($closest !== $cluster) {
                     if (! isset($attach[$closest])) {
-                        $attach[$closest] = new \SplObjectStorage;
+                        $attach[$closest] = new \SplObjectStorage();
                     }
 
                     if (! isset($detach[$cluster])) {
-                        $detach[$cluster] = new \SplObjectStorage;
+                        $detach[$cluster] = new \SplObjectStorage();
                     }
 
                     $attach[$closest]->attach($point);
diff --git a/tests/Kmeans/ClusterTest.php b/tests/Kmeans/ClusterTest.php
index 022e4ec..ba69dcb 100644
--- a/tests/Kmeans/ClusterTest.php
+++ b/tests/Kmeans/ClusterTest.php
@@ -106,7 +106,7 @@ public function testAttachAll()
             new Point($space, [2,2]),
         ];
 
-        $storage = new \SplObjectStorage;
+        $storage = new \SplObjectStorage();
         foreach ($points as $point) {
             $storage->attach($point);
         }
@@ -129,7 +129,7 @@ public function testDetachAll()
             $cluster->attach($point);
         }
 
-        $storage = new \SplObjectStorage;
+        $storage = new \SplObjectStorage();
         foreach ($points as $point) {
             $storage->attach($point);
         }