start c++ implementation

.gitignore

@@ -1 +1 @@
-*.class
+*.class

README.md

@@ -1,31 +1,31 @@
-CS426 - Operating Systems
+CS426 - Operating Systems
-
+
-# Collatz assignment
+# Collatz assignment
-
+
-The Collatz conjecture is simple.  It says that for every starting number
+The Collatz conjecture is simple.  It says that for every starting number
-the sequence below always eventually gets to a 1.
+the sequence below always eventually gets to a 1.
-    f(n) = n/2 if n is even
+    f(n) = n/2 if n is even
-    f(n+1) = 3n+1 if n is odd
+    f(n+1) = 3n+1 if n is odd
-
+
-For example.
+For example.
-  17 -> 52 -> 26 -> 13 -> 40 -> 20 -> 10 -> 5 -> 16 -> 8 -> 4 -> 2 -> 1
+  17 -> 52 -> 26 -> 13 -> 40 -> 20 -> 10 -> 5 -> 16 -> 8 -> 4 -> 2 -> 1
-
+
-
+
-### Your mission is to find the starting number that is less than 1,000,000 with the longest sequence.
+### Your mission is to find the starting number that is less than 1,000,000 with the longest sequence.
-
+
-This might take a long time.  To make it faster, you might cache previous
+This might take a long time.  To make it faster, you might cache previous
-answers. Suppose you have an array prev[].  Prev[n] is the length of the 
+answers. Suppose you have an array prev[].  Prev[n] is the length of the 
-sequence starting at n.  If, when computing a sequence, you ever get to a
+sequence starting at n.  If, when computing a sequence, you ever get to a
-number with a value in prev[], you can use that instead of continuing the 
+number with a value in prev[], you can use that instead of continuing the 
-computation.
+computation.
-
+
-If you have multiple threads, you must use good locking.
+If you have multiple threads, you must use good locking.
-
+
-### Objectives
+### Objectives
-
+
-* Can compute the collatz sequence length for a given number.
+* Can compute the collatz sequence length for a given number.
-* Can find the longest sequence.
+* Can find the longest sequence.
-* Uses Java threads
+* Uses Java threads
-* Uses C++ Threads
+* Uses C++ Threads
-* Uses the array prev[] above.
+* Uses the array prev[] above.
 * Does better load balancing that simple partitioning.

cpp_src/Makefile

@@ -0,0 +1,17 @@
+CSW = -O3 -Wall
+LSW = -lfd
+
+all:
+	make collatz
+
+collatz: collatz.o Makefile
+	g++ collatz.o -o collatz
+
+collatz.o: collatz.cc Makefile
+	g++ collatz.cc -c -o collatz.o $(CSW)
+
+collatz.cc: collatz.h Makefile
+	touch collatz.cc
+
+clean:
+	touch Makefile; make

cpp_src/collatz.cc

@@ -1,12 +1,38 @@
-#import <unistd.h>
+// Ben Harris
-
+
-
+#import <unistd.h>
-
+#import <cstdlib>
-int collatz(int start) {
+#import <string>
-  int cnt = 0;
+#import <iostream>
-  while(start != 1) {
+#import "collatz.h"
-    cnt++;
+using namespace std;
-    start = start % 2 == 0 ? start/2 : 3*start + 1;
+
-  }
+int *prev = new int[1000000];
-  return cnt;
+int maxcnt = 0, maxsteps = 0;
-}
+
+int main (int argc, char **argv) {
+  cout << "cCollatz" << endl;
+  for (int i = 1; i <= 100000; i++) {
+    cout << i << "\tnum of steps: " << collatz(i) << endl;
+  }
+  cout << "Longest path was " << maxsteps << " steps for " << maxcnt << endl;
+}
+
+int collatz (int start) {
+  int cnt = 0;
+  int initval = start;
+  while(start != 1) {
+    cnt++;
+    if (start < 1000000 && prev[start] != 0) {
+      start = prev[start];
+      continue;
+    }
+    start = start % 2 == 0 ? start/2 : 3*start + 1;
+  }
+  prev[start] = cnt;
+  if (cnt > maxcnt) {
+    maxcnt = initval;
+    maxsteps = cnt;
+  }
+  return cnt;
+}

cpp_src/collatz.h

@@ -0,0 +1,10 @@
+// Ben Harris
+
+#ifndef _COLLATZ_h_
+#define _COLLATZ_h_
+
+// method definitions
+int main(int argc, char **argv);
+int collatz(int start);
+
+#endif

java_src/Collatz.java

@@ -1,37 +1,39 @@
-class Collatz {
+// Ben Harris
-
+
-  int prev[] = new int[1000000];
+class Collatz {
-  int max = 0;
+
-  int maxsteps = 0;
+  int prev[] = new int[1000000];
-
+  int max = 0;
-  public static void main(String[] args) {
+  int maxsteps = 0;
-    System.out.println("collatz calc");
+
-
+  public static void main(String[] args) {
-    Collatz c = new Collatz();
+    System.out.println("javaCollatz");
-
+
-    for(int i = 1; i <= 100000; i++){
+    Collatz c = new Collatz();
-      System.out.println(i + "\tnum of steps: " + c.collatz(i));
+
-    }
+    for(int i = 1; i <= 100000; i++){
-
+      System.out.println(i + "\tnum of steps: " + c.collatz(i));
-    System.out.println("Longest path was at " + c.max + " with " + c.maxsteps + " steps.");
+    }
-  }
+
-
+    System.out.println("Longest path was at " + c.max + " with " + c.maxsteps + " steps.");
-  int collatz(int start) {
+  }
-    int cnt = 0;
+
-    int initval = start;
+  int collatz(int start) {
-    while(start != 1) {
+    int cnt = 0;
-      cnt++;
+    int initval = start;
-      if(start < 1000000 && prev[start] != 0) {
+    while(start != 1) {
-        start = prev[start];
+      cnt++;
-        continue;
+      if(start < 1000000 && prev[start] != 0) {
-      }
+        start = prev[start];
-      start = start % 2 == 0 ? start/2 : 3*start + 1;
+        continue;
-    }
+      }
-    prev[start] = cnt;
+      start = start % 2 == 0 ? start/2 : 3*start + 1;
-    if(cnt > max){
+    }
-      max = initval;
+    prev[start] = cnt;
-      maxsteps = cnt;
+    if(cnt > max){
-    }
+      max = initval;
-    return cnt;
+      maxsteps = cnt;
-  }
+    }
+    return cnt;
+  }
 }