init commit

archive/design pattern/iterator.cpp

@@ -0,0 +1,71 @@
+#include <iostream>
+#include <vector>
+using namespace std;
+
+class AbstractIterator
+{
+public:
+    virtual void *next() = 0;
+};
+class PageIterator : public AbstractIterator
+{
+protected:
+    vector<void *> v;
+    int pos = 0;
+
+public:
+    PageIterator(vector<void *> v)
+    {
+        this->v = v;
+    }
+    void *next()
+    {
+        if (pos >= v.size())
+        {
+            return NULL;
+        }
+
+        return v[pos++];
+    }
+};
+class List
+{
+protected:
+    vector<void *> v;
+
+public:
+    void add(void *data)
+    {
+        v.insert(v.end(), data);
+    }
+    AbstractIterator *page(int page)
+    {
+        vector<void *> p(v.begin() + ((page - 1) * 5), v.begin() + (page * 5));
+        return new PageIterator(p);
+    }
+};
+
+int main()
+{
+    List *list = new List();
+    for (int i = 0; i < 8; i++)
+    {
+        int *tmp = (int *)malloc(sizeof(int));
+        *tmp = i;
+        list->add(tmp);
+    }
+    AbstractIterator *iterator = list->page(1);
+    void *next;
+    cout << "page1:\n";
+    while ((next = iterator->next()) != NULL)
+    {
+        cout << *(int *)next << "\t";
+    }
+    cout << "\npage2:\n";
+    iterator = list->page(2);
+    while ((next = iterator->next()) != NULL)
+    {
+        cout << *(int *)next << "\t";
+    }
+    return 0;
+}