const iterator + separate iterator from list.h

c_os/user/demo/ArrayListDemo.cc

@@ -92,6 +92,11 @@ void ArrayListDemo::run() {
         kout << "List contains element: " << dec << i << endl;
     }
 
+    kout << "Const iterator" << endl;
+    for (const int i : this->list) {
+        kout << "List contains element: " << dec << i << endl;
+    }
+
     kout.unlock();
     scheduler.exit();
 }

c_os/user/lib/Iterator.h

@@ -0,0 +1,40 @@
+#ifndef __Iterator_Include_H_
+#define __Iterator_Include_H_
+
+// This iterator works for structures where the elements are adjacent in memory.
+// For things like LinkedList, the operator++ has to be overriden to implement the traversal.
+template<typename T>
+class Iterator {
+public:
+    using Type = T;
+
+protected:
+    Type* ptr;
+
+public:
+    Iterator(Type* ptr) : ptr(ptr) {}
+
+    // I only implement the least necessary operators
+    virtual Iterator& operator++() {
+        this->ptr = this->ptr + 1;
+        return *this;
+    }
+
+    Type* operator->() {
+        return this->ptr;
+    }
+
+    Type& operator*() {
+        return *this->ptr;
+    }
+
+    bool operator==(const Iterator& other) const {
+        return this->ptr == other.ptr;
+    }
+
+    bool operator!=(const Iterator& other) const {
+        return !(*this == other);  // Use our == implementation
+    }
+};
+
+#endif

c_os/user/lib/LinkedList.h

@@ -23,11 +23,11 @@ public:
 
 // Implement linked traversal by extending the ListIterator
 template<typename T>
-class LinkedListIterator : public ListIterator<T> {
+class LinkedListIterator : public Iterator<T> {
 public:
-    using Type = typename ListIterator<T>::Type;
+    using Type = typename Iterator<T>::Type;
 
-    LinkedListIterator(Type* ptr) : ListIterator<T>(ptr) {}
+    LinkedListIterator(Type* ptr) : Iterator<T>(ptr) {}
 
     LinkedListIterator& operator++() override {
         // ptr is of type Wrapper<T>*

c_os/user/lib/List.h

@@ -2,47 +2,11 @@
 #define __LIST_INCLUDE_H_
 
 #include "lib/OutStream.h"
+#include "user/lib/Iterator.h"
 
 // Define the list interface for ArrayList/LinkedList implementations with support for Iterators/ranged based for loops
 
-// TODO: Does it only work on lists?
-// This iterator works for structures where the elements are adjacent in memory.
-// For things like LinkedList, the operator++ has to be overriden to implement the traversal.
-template<typename T>
-class ListIterator {
-public:
-    using Type = T;
-
-protected:
-    Type* ptr;
-
-public:
-    ListIterator(Type* ptr) : ptr(ptr) {}
-
-    // I only implement the least necessary operators
-    virtual ListIterator& operator++() {
-        this->ptr = this->ptr + 1;
-        return *this;
-    }
-
-    Type* operator->() {
-        return this->ptr;
-    }
-
-    Type& operator*() {
-        return *this->ptr;
-    }
-
-    bool operator==(const ListIterator& other) const {
-        return this->ptr == other.ptr;
-    }
-
-    bool operator!=(const ListIterator& other) const {
-        return !(*this == other);  // Use our == implementation
-    }
-};
-
-template<typename T, typename I = ListIterator<T>>
+template<typename T, typename I = Iterator<T>>
 class List {
 public:
     using Type = T;      // We make the template argument accessible from the subclasses
@@ -55,6 +19,8 @@ protected:
 public:
     Iterator begin() { return Iterator(this->begin_ptr()); }
     Iterator end() { return Iterator(this->end_ptr()); }
+    constexpr Iterator begin() const { return this->begin(); }
+    constexpr Iterator end() const { return this->end(); }
 
     virtual unsigned int insert_at(Type e, unsigned int i) = 0;
     virtual unsigned int insert_first(Type e) = 0;