update package names + lab4

test/dev/sowinski/comp1510/strings/StringReverse.java

@@ -0,0 +1,96 @@
+package dev.sowinski.comp1510.strings;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+
+/**
+ * StringReverse test different methods to reverse strings.
+ * @author Braeden Sowinski
+ * @version 1.0.0
+ */
+public class StringReverse {
+    
+    /**
+     * linearReverse reverse strings by looping over each element.
+     * @param s string to reverse
+     * @return reversed string as String
+     */
+    public static String linearReverse(String s) {
+        String n = "";
+        for (int i = s.length() - 1; i >= 0; i--) {            
+            n += s.charAt(i);
+        }
+        return n;
+    }
+    
+    /**
+     * halfLinearReverse reverses strings by only looping
+     * over half of the string.
+     * @param s string to reverse
+     * @return reversed string
+     */
+    public static String halfLinearReverse(String s) {
+        char r;
+        char[] n = s.toCharArray();
+        for (int i = 0; i < n.length / 2; i++) {
+            r = n[n.length - 1 - i];
+            n[n.length - 1 - i] = n[i];
+            n[i] = r;
+        }
+        return new String(n);
+    }
+
+    /**
+     * main program entry.
+     * @param args unused
+     */
+    public static void main(String[] args) {
+        char[] charset = {
+            'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 
+            'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 
+            's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '1', 
+            '2', '3', '4', '5', '6', '7', '8', '9', '0'
+        };
+        String test = new String(charset);
+        
+        long start;
+        long end;
+        final int upperBound = 100000;
+        final int micro = 1000;
+
+        try {
+            PrintWriter myWriter = new PrintWriter("output.csv", "UTF-8");
+        
+            for (int i = 0; i < upperBound; i++) {
+                start = System.nanoTime();
+                String r1 = new StringBuffer(test).reverse().toString();
+                r1.length();
+                end = System.nanoTime();
+                int duration1 = (int) ((end - start) / micro);
+                
+                start = System.nanoTime();
+                r1 = halfLinearReverse(test);
+                end = System.nanoTime();
+                int duration3 = (int) ((end - start) / micro);
+    
+                int len = test.length() + 1;
+                System.out.println(len - 1);
+      
+                int rand = (int) (Math.random() * charset.length);
+                test += charset[rand];
+                
+                String data = len + ","
+                        + duration1 + ","
+                        + duration3;
+                
+                myWriter.println(data);
+            }
+            
+            myWriter.close();
+            System.out.println("Done");
+        } catch (IOException e) {
+            System.out.println("An error occured!");
+            e.printStackTrace();
+        }
+    }
+}

test/dev/sowinski/comp1510/strings/tinker.py

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+import matplotlib.pyplot as plt
+import csv
+import numpy
+
+x = []
+y1 = []
+y2 = []
+
+with open('output.csv', newline='') as csvfile:
+  spamreader = csv.reader(csvfile, delimiter=',')
+  # i = 0
+  for row in spamreader:
+    # i += 1
+    x.append(int(row[0]))
+    y1.append(int(row[1]))
+    y2.append(int(row[2]))
+    # if i == 100: break
+
+x = x[0::250]
+y1 = y1[0::250]
+y2 = y2[0::250]
+
+plt.xlabel("String Length")
+plt.ylabel("Microseconds (0.000001 seconds)")
+
+plt.plot(x, y1, label="Java String Reverse")
+plt.plot(x, y2, label="Half Linear Reverse")
+
+z1 = numpy.polyfit(x, y1, 1)
+p1 = numpy.poly1d(z1)
+plt.plot(x, p1(x), "r--", label="Java String Reverse Trend")
+
+z1 = numpy.polyfit(x, y2, 1)
+p1 = numpy.poly1d(z1)
+plt.plot(x, p1(x), "g--", label="Half Linear Reverse Trend")
+
+plt.legend()
+plt.show()