Week12 fibonacci

2 files changed, 145 insertions, 0 deletions

diff --git a/Week12 Fibonacci/src/com/camilstaps/fibonacci/ParFib.java b/Week12 Fibonacci/src/com/camilstaps/fibonacci/ParFib.java
new file mode 100644
index 0000000..098ba5a
--- /dev/null
+++ b/Week12 Fibonacci/src/com/camilstaps/fibonacci/ParFib.java
@@ -0,0 +1,91 @@
+/*
+ * The MIT License (MIT)
+ * 
+ * Copyright (c) 2015 Camil Staps <info@camilstaps.nl>
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.camilstaps.fibonacci;
+
+/**
+ * Calculate a fibonacci number
+ * @author Camil Staps s4498062
+ */
+public class ParFib implements Runnable {
+    
+    private final int n;
+    private int result = 0;
+    
+    /**
+     * Create a new instance
+     * @param n the index of the fibonacci number to calculate
+     */
+    public ParFib(int n) {
+        this.n = n;
+    }
+
+    @Override
+    public void run() {
+        calculate(n);
+    }
+    
+    public int getResult() {
+        return result;
+    }
+    
+    /**
+     * Calculate the nth number of the Fibonacci sequence.
+     * 
+     * This implementation uses two threads if n > 2: one to calculate the 
+     * (n-1)th fibonacci number, and one to calculate the (n-2)th fibonacci
+     * number. That is a really silly approach, since many threads will be
+     * created and many numbers will be calculated many times. 
+     * As an example, to calculate for n=10, we will calculate the 8th number
+     * twice: once for n=10 (10-2=8) and once for n=9 (9-1=8). The 7th number
+     * will be calculated thrice, and this amount increases for lower numbers.
+     * But hey, the assignment asked for a solution with threads.
+     * 
+     * @param n 
+     */
+    private void calculate(int n) {
+        if (n < 3) {
+            result = 1;
+            return;
+        }
+        
+        ParFib pf1 = new ParFib(n - 1);
+        ParFib pf2 = new ParFib(n - 2);
+        Thread t1 = new Thread(pf1);
+        Thread t2 = new Thread(pf2);
+        t1.start();
+        t2.start();
+        
+        try {
+            t1.join();
+            t2.join();
+        } catch (InterruptedException ex) {
+            System.err.println(ex.toString());
+        }
+        
+        if (pf1.getResult() != 0 && pf2.getResult() != 0) {
+            result = pf1.getResult() + pf2.getResult();
+        }
+    }
+    
+}
diff --git a/Week12 Fibonacci/src/com/camilstaps/fibonacci/Week12Fibonacci.java b/Week12 Fibonacci/src/com/camilstaps/fibonacci/Week12Fibonacci.java
new file mode 100644
index 0000000..2115cfb
--- /dev/null
+++ b/Week12 Fibonacci/src/com/camilstaps/fibonacci/Week12Fibonacci.java
@@ -0,0 +1,54 @@
+/*
+ * The MIT License (MIT)
+ * 
+ * Copyright (c) 2015 Camil Staps <info@camilstaps.nl>
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.camilstaps.fibonacci;
+
+/**
+ * Solutions to week 12, part 2
+ * @author Camil Staps s4498062
+ */
+public class Week12Fibonacci {
+
+    /**
+     * Usage: java Week12Fibonacci n
+     * Where n is the index of the number from the fibonacci sequence you want
+     * @param args the command line arguments
+     */
+    public static void main(String[] args) {
+        if (args.length != 1) {
+            System.err.println("Usage: java Week12Fibonacci n");
+            System.exit(-1);
+        }
+        
+        ParFib pf = new ParFib(Integer.parseInt(args[0]));
+        Thread t = new Thread(pf);
+        t.start();
+        try {
+            t.join();
+            System.out.println(Integer.toString(pf.getResult()));
+        } catch (InterruptedException ex) {
+            System.err.println(ex.toString());
+        }
+    }
+    
+}