1 files changed, 24 insertions, 0 deletions
diff --git a/oop/03-interfaces/Calculator.java b/oop/03-interfaces/Calculator.java
new file mode 100644
index 0000000..aa716b0
--- /dev/null
+++ b/oop/03-interfaces/Calculator.java
@@ -0,0 +1,24 @@
+//abstract interface Calculator {
+interface Calculator {
+	public final static double PI = 3.14;
+
+	// double PI = 3.14;
+	// public static double PI = 3.14;
+	// public final double PI = 3.14;
+	// final double PI = 3.14;
+	// static double PI = 3.14;
+
+	public int add(int a, int b);
+	// int add(int a, int b);
+	// abstract int add(int a, int b);
+	// public abstract int add(int a, int b);
+
+	// static int add(int a, int b); // Not allowed
+	// int add(int a, int b); // Allowed
+	
+//	public int subtract(int a, int b);
+//	int subtract(int a, int b);
+	abstract int subtract(int a, int b);
+
+	public double divide(double a, double b);
+}