5 files changed, 47 insertions, 24 deletions
diff --git a/src/jcgp/function/Addition.java b/src/jcgp/function/Addition.java
index f40bc24..3a8f123 100644
--- a/src/jcgp/function/Addition.java
+++ b/src/jcgp/function/Addition.java
@@ -1,5 +1,6 @@
 package jcgp.function;
 
+import jcgp.exceptions.InvalidArgumentsException;
 import jcgp.population.Connection;
 
 public class Addition extends Function {
@@ -11,7 +12,12 @@ public class Addition extends Function {
 		if (connections.length < arity) {
 			throw new InvalidArgumentsException("Not enough connections were given.");
 		} else if (connections[0].getValue() instanceof Integer) {
-			return ((Integer) connections[0].getValue()) + ((Integer) connections[1].getValue());
+			Integer arg1 = ((Integer) connections[0].getValue());
+			Integer arg2 = ((Integer) connections[1].getValue());
+			Integer result = arg1 + arg2;
+			
+			System.out.println(arg1 + " + " + arg2 + " = " + result);
+			return result;
 		} else {
 			throw new InvalidArgumentsException("Wrong data type, this function takes Integer.");
 		}
diff --git a/src/jcgp/function/Function.java b/src/jcgp/function/Function.java
index 118131a..584421a 100644
--- a/src/jcgp/function/Function.java
+++ b/src/jcgp/function/Function.java
@@ -1,11 +1,11 @@
 package jcgp.function;
 
+import jcgp.exceptions.InvalidArgumentsException;
 import jcgp.population.Connection;
-import jcgp.population.InsufficientConnectionsException;
 
 public abstract class Function {
 		
-	public abstract Object run(Connection ... connections) throws InsufficientConnectionsException;
+	public abstract Object run(Connection ... connections) throws InvalidArgumentsException;
 	
 	public abstract int getArity();
 	
diff --git a/src/jcgp/function/InvalidArgumentsException.java b/src/jcgp/function/InvalidArgumentsException.java
deleted file mode 100644
index cf55937..0000000
--- a/src/jcgp/function/InvalidArgumentsException.java
+++ /dev/null
@@ -1,20 +0,0 @@
-package jcgp.function;
-
-public class InvalidArgumentsException extends RuntimeException {
-
-	/**
-	 * 
-	 */
-	private static final long serialVersionUID = 2675108124600817777L;
-	private String reason;
-	
-	public InvalidArgumentsException(String reason) {
-		super();
-		this.reason = reason;
-	}
-	
-	public String getReason() {
-		return reason;
-	}
-
-}
diff --git a/src/jcgp/function/Multiplication.java b/src/jcgp/function/Multiplication.java
new file mode 100644
index 0000000..986faa8
--- /dev/null
+++ b/src/jcgp/function/Multiplication.java
@@ -0,0 +1,31 @@
+package jcgp.function;
+
+import jcgp.exceptions.InvalidArgumentsException;
+import jcgp.population.Connection;
+
+public class Multiplication extends Function {
+
+	private int arity = 2;
+
+	@Override
+	public Object run(Connection... connections) {
+		if (connections.length < arity) {
+			throw new InvalidArgumentsException("Not enough connections were given.");
+		} else if (connections[0].getValue() instanceof Integer) {
+			Integer arg1 = ((Integer) connections[0].getValue());
+			Integer arg2 = ((Integer) connections[1].getValue());
+			Integer result = arg1 * arg2;
+			
+			System.out.println(arg1 + " * " + arg2 + " = " + result);
+			return result;
+		} else {
+			throw new InvalidArgumentsException("Wrong data type, this function takes Integer.");
+		}
+	}
+
+	@Override
+	public int getArity() {
+		return arity;
+	}
+
+}
diff --git a/src/jcgp/function/Subtraction.java b/src/jcgp/function/Subtraction.java
index d785614..cfbb907 100644
--- a/src/jcgp/function/Subtraction.java
+++ b/src/jcgp/function/Subtraction.java
@@ -1,5 +1,6 @@
 package jcgp.function;
 
+import jcgp.exceptions.InvalidArgumentsException;
 import jcgp.population.Connection;
 
 public class Subtraction extends Function {
@@ -11,7 +12,12 @@ public class Subtraction extends Function {
 		if (connections.length < arity) {
 			throw new InvalidArgumentsException("Not enough connections were given.");
 		} else if (connections[0].getValue() instanceof Integer) {
-			return ((Integer) connections[0].getValue()) - ((Integer) connections[1].getValue());
+			Integer arg1 = ((Integer) connections[0].getValue());
+			Integer arg2 = ((Integer) connections[1].getValue());
+			Integer result = arg1 - arg2;
+			
+			System.out.println(arg1 + " - " + arg2 + " = " + result);
+			return result;
 		} else {
 			throw new InvalidArgumentsException("Wrong data type, this function takes Integer.");
 		}