diff --git a/Test/abstract_inheritance_test.java b/Test/abstract_inheritance_test.java
new file mode 100644
index 0000000..806705e
--- /dev/null
+++ b/Test/abstract_inheritance_test.java
@@ -0,0 +1,41 @@
+import java.util.List;
+import java.util.Arrays;
+
+public class Test {
+	public static void main(String[] args) {
+		Child child = new Child();
+		child.hello();
+		child.hi();
+		child.sup();
+		System.out.println(child.n);
+	}
+}
+
+abstract public class Mother {
+	public int n;
+	public Mother() {
+	}
+	public Mother(int n) {
+		this.n = n;
+	}
+	abstract public void hello();
+	public void hi() {
+		System.out.println("hi");
+	}
+}
+
+public class Child extends Mother {
+	public Child() {
+	}
+	public Child(int n) {
+		super(n);
+	}
+
+	@Override
+	public void hello() {
+		System.out.println("hello");
+	}
+	public void sup() {
+		System.out.println("sup");
+	}
+}
diff --git a/Test/quicksort.java b/Test/quicksort.java
new file mode 100644
index 0000000..d1c3956
--- /dev/null
+++ b/Test/quicksort.java
@@ -0,0 +1,33 @@
+import java.util.Arrays;
+
+public class Test {
+	static private void quicksort(int[] ar, int a, int b) {
+		if (a < b) {
+			int i = partition(ar, a, b);
+			quicksort(ar, a, i);
+			quicksort(ar, i+1, b);
+		}
+	}
+
+	static private int partition(int[] ar, int a, int b) {
+		int p = ar[a+(b-a)/2];
+		int c = a;
+		int d = b;
+		while (true) {
+			do { c++; } while (ar[c]<p);
+			do { d--; } while (ar[d]>p);
+			System.out.println(Arrays.toString(ar));
+			System.out.println(String.valueOf(c)+":"+String.valueOf(d));
+			if (c>=d) return d;
+			int t = ar[c];
+			ar[c] = ar[d];
+			ar[d] = t;
+		}
+	}
+
+	public static void main(String[] args) {
+		int[] array = {1, 0, 1, 2};
+		quicksort(array, 0, array.length-1);
+		System.out.println(Arrays.toString(array));
+	}
+}
diff --git a/Test/test.java b/Test/test.java
index 806705e..d1c3956 100644
--- a/Test/test.java
+++ b/Test/test.java
@@ -1,41 +1,33 @@
-import java.util.List;
 import java.util.Arrays;
 
 public class Test {
+	static private void quicksort(int[] ar, int a, int b) {
+		if (a < b) {
+			int i = partition(ar, a, b);
+			quicksort(ar, a, i);
+			quicksort(ar, i+1, b);
+		}
+	}
+
+	static private int partition(int[] ar, int a, int b) {
+		int p = ar[a+(b-a)/2];
+		int c = a;
+		int d = b;
+		while (true) {
+			do { c++; } while (ar[c]<p);
+			do { d--; } while (ar[d]>p);
+			System.out.println(Arrays.toString(ar));
+			System.out.println(String.valueOf(c)+":"+String.valueOf(d));
+			if (c>=d) return d;
+			int t = ar[c];
+			ar[c] = ar[d];
+			ar[d] = t;
+		}
+	}
+
 	public static void main(String[] args) {
-		Child child = new Child();
-		child.hello();
-		child.hi();
-		child.sup();
-		System.out.println(child.n);
-	}
-}
-
-abstract public class Mother {
-	public int n;
-	public Mother() {
-	}
-	public Mother(int n) {
-		this.n = n;
-	}
-	abstract public void hello();
-	public void hi() {
-		System.out.println("hi");
-	}
-}
-
-public class Child extends Mother {
-	public Child() {
-	}
-	public Child(int n) {
-		super(n);
-	}
-
-	@Override
-	public void hello() {
-		System.out.println("hello");
-	}
-	public void sup() {
-		System.out.println("sup");
+		int[] array = {1, 0, 1, 2};
+		quicksort(array, 0, array.length-1);
+		System.out.println(Arrays.toString(array));
 	}
 }