update preemption demo to variable thread num

c_os/user/demo/PreemptiveThreadDemo.cc

@@ -2,34 +2,37 @@
 
 void PreemptiveLoopThread::run() {
     int cnt = 0;
+
     while (true) {
         // Basic synchronization by semaphore
         sem->p();
 
-        kout.setpos(55, this->id);
-        kout << this->id << ": " << dec << cnt++ << endl;
+        // Saving + restoring kout position doesn't help much as preemption still occurs,
+        // only LoopThreads are synchronized, so other output will be disturbed sometimes
+        // kout.setpos(55, this->id);
+        // kout << fillw(3) << this->id << fillw(0) << ": " << dec << cnt++ << endl;
 
         sem->v();
     }
 }
 
 void PreemptiveThreadDemo::run() {
-    kout << "PreemptiveThreadDemo ====================================" << endl;
     kout << "Initializing Semaphore" << endl;
     Semaphore* sem = new Semaphore(1);  // Create this semaphore on the heap as this thread exits itself,
                                         // so stack allocated objects will be lost
 
-    kout << "Allocating LoopThread A" << endl;
-    Thread* cntA = new PreemptiveLoopThread(0, sem);
-    kout << "Allocating LoopThread B" << endl;
-    Thread* cntB = new PreemptiveLoopThread(1, sem);
-    kout << "Allocating LoopThread C" << endl;
-    Thread* cntC = new PreemptiveLoopThread(2, sem);
+    // TODO: Threads disappear, the fewer loop the faster they vanish
+    //       It seems like this happens with exactly 3 or 4 loopthreads
+    Thread* threads[this->number_of_threads];
+    kout << "Allocating LoopThreads" << endl;
+    for (unsigned int i = 0; i < this->number_of_threads; ++i) {
+        threads[i] = new PreemptiveLoopThread(i, sem);
+    }
 
     kout << "Adding threads to ready queue" << endl;
-    scheduler.ready(cntA);
-    scheduler.ready(cntB);
-    scheduler.ready(cntC);
+    for (unsigned int i = 0; i < this->number_of_threads; ++i) {
+        scheduler.ready(threads[i]);
+    }
 
     kout << "Exiting main thread" << endl;
     scheduler.exit();

c_os/user/demo/PreemptiveThreadDemo.h

@@ -24,8 +24,10 @@ class PreemptiveThreadDemo : public Thread {
 private:
     PreemptiveThreadDemo(const PreemptiveThreadDemo& copy) = delete;  // Verhindere Kopieren
 
+    unsigned int number_of_threads;
+
 public:
-    PreemptiveThreadDemo() {
+    PreemptiveThreadDemo(unsigned int n) : number_of_threads(n) {
         kout << "Initialized PreemptiveThreadDemo" << endl;
     }