opprenskning

lab_3/sequences-int/doubly-linked-list.h

@@ -2,8 +2,8 @@
 #define DOUBLY_LINKED_LIST_H
 
 #include <cassert>
+#include <cstddef>
 #include "queue.h"
-#include "sequence.h"
 
 namespace seq
 {

lab_3/sequences-int/dynamic-array.cpp

@@ -1,6 +1,8 @@
 #include <algorithm>
 #include <cassert>
+#include <iostream>
 
+#include "queue.h"
 #include "dynamic-array.h"
 
 using namespace seq;
@@ -14,7 +16,6 @@ void DynamicArray::clear()
    this->capacity = 0;
 }
 
-// insert an item at index i
 void DynamicArray::enqueue(int value)
 {
    int i = this->logical_size;
@@ -40,7 +41,7 @@ void DynamicArray::enqueue(int value)
       
       // copy all of temp_storage into values[i+1] to values[logical_size]
       std::copy(temp_storage, temp_storage + shifted_elements, &this->values[i+1]);
-      delete temp_storage;
+      delete[] temp_storage;
    }
    
    // now we can write the inserted item into values[i]
@@ -48,29 +49,35 @@ void DynamicArray::enqueue(int value)
    this->values[i] = value;
 }
 
-// remove the item at index i
 int DynamicArray::dequeue()
 {
-   int i = 0;
    
-   // shift all elements from index i+1 onward one to the left
-   // we use a temporary storage and copy() from <algorithm> to do this efficiently
-   size_t shifted_elements = this->logical_size - i - 1;
-   if(shifted_elements > 0)
-   {
-      int* temp_storage = new int[shifted_elements]();
-      
-      // copy values[i+1] to values[logical_size-1] into temp_storage
-      std::copy(this->values + i+1, this->values + this->logical_size, temp_storage);
-      
-      // copy all of temp_storage into values[i] to values[logical_size-2]
-      std::copy(temp_storage, temp_storage + shifted_elements, &this->values[i]);
-      delete temp_storage;
+   if (this->size() == 0) {
+      return 0;
    }
-   this->logical_size--;  // with this, we are done with the task
+   int i = 0;
+   // Save the first element wich we want to return:
+   int outgoing = this->values[0];
    
-   // now let us see whether we have deleted so many items that we should resize to save memory
-   if(this->capacity/2 >= this->logical_size) this->resize(this->capacity/2);
+   // shift all elements from onward one to the left
+   size_t shifted_elements = this->logical_size - 1;
+   
+   int* temp_storage = new int[shifted_elements]();
+   
+   // copy values[i+1] to values[logical_size-1] into temp_storage
+   std::copy(this->values + 1, this->values + this->logical_size, temp_storage);
+   
+   // copy all of temp_storage into values[i] to values[logical_size-2]
+   std::copy(temp_storage, temp_storage + shifted_elements, &this->values[i]);
+   delete[] temp_storage;
+   if (!this->empty()) {
+      this->logical_size--;  // with this, we are done with the task
+   
+      // now let us see whether we have deleted so many items that we should resize to save memory
+      if(this->capacity/2 >= this->logical_size) this->resize(this->capacity/2);
+
+   }
+   return outgoing;
 }
 
 // allocate static array with "new_capacity" elements,

lab_3/sequences-int/dynamic-array.h

@@ -1,5 +1,4 @@
 #include "queue.h"
-#include "sequence.h"
 
 namespace seq
 {

lab_3/sequences-int/sequence-test.cpp

@@ -1,6 +1,7 @@
 #include <cassert>
 #include <chrono>
 #include <iostream>
+#include <queue>
 
 #include "dynamic-array.h"
 #include "queue.h"
@@ -12,11 +13,19 @@ namespace
    /*
     * run a simple test
     */
-   void test_sequence(seq::Queue* sqn, int n, int m, std::ostream* os)
+   void test_queue(seq::Queue* sqn, int n, int m, std::ostream* os)
    {
       assert((m > 0) && (n > m));
       if(os) *os << "Enqueue even numbers from 0 to " << 2*(n-1) << ".\n";
       for(int i = 0; i < n; i++) sqn->enqueue(2*i);
+      for(int i = 0; i < n; i++) sqn->dequeue();
+   }
+   void test_queue(std::queue<int>* sqn, int n, int m, std::ostream* os)
+   {
+      assert((m > 0) && (n > m));
+      if(os) *os << "Enqueue even numbers from 0 to " << 2*(n-1) << ".\n";
+      for(int i = 0; i < n; i++) sqn->push(2*i);
+      for(int i = 0; i < n; i++) sqn->pop();
    }
    
    /*
@@ -24,16 +33,38 @@ namespace
     */
    float test_with_time_measurement(seq::Queue* sqn, int iterations)
    {
-      int sequence_length = 200001;
+      int queue_length = 20001;
       int deletions = 10;
-      test_sequence(sqn, sequence_length, deletions, &std::cout);
+      test_queue(sqn, queue_length, deletions, &std::cout);
 
       int log_entries = 10;
       std::cout << "\nNow repeat the above " << iterations << " times:\n";
       auto t0 = std::chrono::high_resolution_clock::now();
       for(int i = 0; i < iterations; i++)
       {
-         test_sequence(sqn, sequence_length, deletions, nullptr);
+         test_queue(sqn, queue_length, deletions, nullptr);
+         if((i+1) % (iterations/log_entries) == 0)
+         {
+            std::cout << "\t" << i+1 << "\n";
+            std::cout.flush();  // make sure that status output is shown without delay
+         }
+      }
+      auto t1 = std::chrono::high_resolution_clock::now();
+      return 1.0e-06 * std::chrono::duration_cast<std::chrono::microseconds>(t1-t0).count();
+   }
+
+   float test_with_time_measurement(std::queue<int>* sqn, int iterations)
+   {
+      int queue_length = 20001;
+      int deletions = 10;
+      test_queue(sqn, queue_length, deletions, &std::cout);
+
+      int log_entries = 10;
+      std::cout << "\nNow repeat the above " << iterations << " times:\n";
+      auto t0 = std::chrono::high_resolution_clock::now();
+      for(int i = 0; i < iterations; i++)
+      {
+         test_queue(sqn, queue_length, deletions, nullptr);
          if((i+1) % (iterations/log_entries) == 0)
          {
             std::cout << "\t" << i+1 << "\n";
@@ -61,7 +92,12 @@ int main()
    seq::DoublyLinkedList dll;
    float dll_time = test_with_time_measurement(&dll, iterations);
    
+   std::cout << "\n\n*** test with std::queue ***\n";
+   std::queue<int> queue;
+   float queue_time = test_with_time_measurement(&queue, iterations);
+   
    std::cout << "\n\nRuntime for dynamic array:\t" << dyna_time << " s\n";
    std::cout << "Runtime for singly linked list:\t" << sll_time << " s\n";
    std::cout << "Runtime for doubly linked list:\t" << dll_time << " s\n";
+   std::cout << "Runtime for std::queue:\t" << queue_time << " s\n";
 }

lab_3/sequences-int/sequence.h

@@ -1,42 +0,0 @@
-#ifndef SEQUENCE_H
-#define SEQUENCE_H
-
-#include <iostream>
-
-namespace seq
-{
-   class Sequence
-   {
-   public:
-      virtual bool empty() const = 0;   // test whether the sequence is empty
-      virtual size_t size() const = 0;  // return the size (number of items in the sequence)
-      
-      // it is the caller's responsibility to ensure that the sequence is not empty when calling front() or back()!
-      virtual int& front() = 0;  // return a reference to the first item
-      virtual int& back() = 0;   // return a reference to the final item
-      
-      // return a reference to the item at position i of the sequence, counting from 0
-      // it is the caller's responsibility that the index is within range
-      virtual int& at(int i) = 0;
-
-      /*
-       * accepts an additional item into the sequence (front or back);
-       * the pushed item is passed by reference, but a copy of it is stored in the Sequence
-       * the Sequence takes ownership of the copy (but not of the original!)
-       */
-      virtual void push(const int& pushed_item) = 0;  // default push operation (front or back)
-      virtual void push_front(const int& pushed_item) = 0;
-      virtual void push_back(const int& pushed_item) = 0;
-
-      virtual void pop() = 0;  // default pop operation (front or back)
-      virtual void pop_front() = 0;  // remove the first element
-      virtual void pop_back() = 0;   // remove the last element
-      virtual void clear() = 0;  // remove all the items from the sequence
-
-      // it is the caller's responsibility that the index is within range
-      virtual void insert_at(int i, const int& inserted_item) = 0;  // insert an item at index i
-      virtual void erase_at(int i) = 0;  // remove the item at index i
-   };
-}
-
-#endif

lab_3/sequences-int/singly-linked-list.cpp

@@ -1,5 +1,5 @@
+#include <cstddef>
 #include "singly-linked-list.h"
-#include <algorithm>
 
 using namespace seq;
 

lab_3/sequences-int/singly-linked-list.h

@@ -2,7 +2,6 @@
 #define SINGLY_LINKED_LIST_H
 
 #include <cassert>
-#include "sequence.h"
 #include "queue.h"
 
 namespace seq
@@ -36,7 +35,7 @@ namespace seq
       bool empty() const { return (this->head == nullptr); }  // test whether the singly linked list is empty
       size_t size() const;  // return the size (number of items in the singly linked list)
 
-      void enqueue(int element);
+      void enqueue(int value);
       int dequeue();
 
       void clear() { while(!this->empty()) this->dequeue(); }  // remove all the items from the list