Merge pull request #12 from urboob21/dev_branch

id 1763269269

Author: urbytes21

docs/uml/patterns_structural_flyweight.drawio.svg

@@ -52,7 +52,7 @@ void arithmeticOperator()
 
     // Increment
     cout << "a = " << a << "\n";
-    int preIn = ++a; // increase a, return copy
+    int preIn = ++a; // increase a, return a
     cout << "preIn = " << preIn << "\n";
 
     cout << "a = " << a << "\n";

src/core/basics/Operations.cpp

@@ -48,6 +48,45 @@ void references()
     std::cout << "By reference: " << b << '\n';
 }
 
+/**
+ * 
+  a (lvalue) 
+  |
+  | std::move(a) (rvalue reference)
+  V
+source (rvalue reference parameter, but it's the lvalue inside the function)
+  |
+  | steal data
+  V
+  b
+ */
+namespace RvalueReference
+{
+    using namespace std;
+
+    // Move-like function taking an rvalue reference as parameter
+    int copyConstructor(int &&x)
+    {
+        // Inside the function, x is a named lvalue that refers to the original object passed in (here, 'a')
+        int result = x * 10; // compute result based on x
+        x = 0;               // reset the original object to 0
+        return result;       // return the computed result
+    }
+
+    void run()
+    {
+        int a{10}; // original value
+
+        // Call function with an rvalue reference using std::move
+        // std::move(a) casts a (lvalue) into an rvalue reference (int&&)
+        int b = copyConstructor(std::move(a));
+
+        cout << b << endl; // prints 100
+        cout << a << endl; // prints 0, because x in the function referred to a and was reset
+    }
+
+}
+
 // A struct that runs code when its object is created
 struct CReferences
 {
@@ -58,6 +97,7 @@ struct CReferences
              << "Compound type: References\n";
 
         references();
+        RvalueReference::run();
     }
 };
 

src/core/datatypes/CReferences.cpp

@@ -158,8 +158,14 @@ namespace Delegate
 }
 
 // *4.  Copy constructor:  initialize an copy object with an existing object
-// Generated if no copy/move constructor or destructor is declared
+// Generated if no copy/move constructor or `destructor` is declared
 // Performs memberwise (shallow) copy
+//  * Copy constructor
+// Object obj1 = obj2
+// Object obj1(obj2)
+// Object obj1{obj2}
+//  * Copy assigment
+// obj1 = obj1
 namespace Copy
 {
     class ICConstructor // C++ will create a public implicit copy constructor for us if we do not provide a one.
@@ -192,14 +198,27 @@ namespace Copy
             cout << "Called  ICConstructor(int x, int y) : m_x{x}, m_y{y} \n";
         }
 
+        // Implicit Copy constructor if there is no desconstrutor
         // using `default` keyword
         // ECConstructor(const ECConstructor &ref) = default;
 
+        // Explicit Copy constructor (a=ECConstructor(b))
         ECConstructor(const ECConstructor &ref) : m_x{ref.m_x}, m_y{ref.m_x}
         {
             cout << "Called  ECConstructor(const ECConstructor& ref) : m_x{ref.m_x}, m_y{ref.m_x} \n";
         }
 
+        // Copy assigment (a=b)
+        ECConstructor &operator=(const ECConstructor &other)
+        {
+            if (this != &other)
+            {
+                this->m_x = other.m_x;
+                this->m_y = other.m_y;
+            }
+            return *this;
+        }
+
         void print() const
         {
             cout << "m_x = " << m_x << ", m_y = " << m_y << "\n";
@@ -246,12 +265,90 @@ namespace Copy
     }
 }
 
-// *4.  Copy constructor:  initialize an copy object with an existing object
-// Generated if no copy/move constructor or destructor is declared
-// Performs memberwise (shallow) copy
-namespace Copy
+// *4. Move Constructor:
+// Move constructor and move assignment transfer resource ownership
+// from one object to another. This is usually cheaper than copying.
+// A move constructor is implicitly generated only if no user-declared
+// copy constructor, move constructor, or destructor exists.
+namespace Move
 {
+    class Model // C++ will create a public implicit copy constructor for us if we do not provide a one.
+    {
+    private:
+        int m_x;
+        int m_y;
 
+    public:
+        Model(int x, int y) : m_x{x}, m_y{y}
+        {
+            cout << "Call constructor \n";
+        }
+
+        ~Model()
+        {
+            cout << "Call destructor \n";
+        }
+
+        Model(const Model &other) : Model(other.m_x, other.m_y)
+        {
+            cout << "Call copy constructor \n";
+        }
+
+        Model &operator=(const Model &other)
+        {
+            cout << "Call copy assigment \n";
+            if (this != &other)
+            {
+                this->m_x = other.m_x;
+                this->m_y = other.m_y;
+            }
+            return *this;
+        }
+
+        Model(Model &&source) noexcept : m_x(source.m_x), m_y(source.m_y)
+        {
+            cout << "Call move constructor\n";
+
+            // reset source
+            source.m_x = 0;
+            source.m_y = 0;
+        }
+
+        Model &operator=(Model &&source) noexcept
+        {
+            cout << "Call move assigment \n";
+            if (this != &source)
+            {
+                this->m_x = source.m_x;
+                this->m_y = source.m_y;
+
+                // reset source
+                source.m_x = 0;
+                source.m_y = 0;
+            }
+
+            return *this;
+        }
+
+        void print() const
+        {
+            cout << "m_x = " << m_x << ", m_y = " << m_y << "\n";
+        }
+    };
+
+    void constructers()
+    {
+        cout << "\n--- Move Constructor Examples ---\n";
+        Model a(10, 20);
+
+        cout << "\nCase 1: Model b = std::move(a);\n";
+        Model b = std::move(a); // move constructor
+
+        cout << "\nCase 2: Model c(5,6); c = std::move(b);\n";
+        Model c(5, 6);
+        c = std::move(b); // move assignment
+        cout << "\n";
+    }
 }
 
 struct CConstructorsAutoRuner
@@ -262,6 +359,7 @@ struct CConstructorsAutoRuner
         Default::constructers();
         Delegate::constructors();
         Copy::constructors();
+        Move::constructers();
     }
 };
 

src/core/datatypes/class/CConstructors.cpp

@@ -92,14 +92,14 @@ namespace
 
             void deepCopy(const Model &source)
             {
-                // first we need to deallocate any value that this Model is holding!
-                delete ptr;
-
                 // sallow copy the normal fields
                 m_x = source.m_x;
                 m_y = source.m_y;
 
+                // deep copy the ptr field
                 // m_data is a pointer, so we need to deep copy it if it is non-null
+                // first we need to deallocate any value that this Model is holding!
+                delete ptr;
                 if (source.ptr != nullptr)
                 {
                     // allocate memory for our copy
@@ -128,12 +128,16 @@ namespace
             }
 
             // Copy constructor
+            // no need to check self-copy [if (this != &source)]
+            // because it cannot happen a(a);  
             Model(const Model &source)
             {
                 this->deepCopy(source);
             }
 
             // Assignment operator
+            // need to check self-copy [if (this != &source)]
+            // because it posible a = a;  
             Model &operator=(const Model &source)
             {
                 if (this != &source)

src/core/datatypes/class/SallowDeepCopying.cpp

@@ -267,7 +267,10 @@ namespace
 
         public:
             explicit FileSystem(const std::string &fileName) : _parent{nullptr}, _name{fileName} {}
-            virtual ~FileSystem() = default;
+            virtual ~FileSystem()
+            {
+                std::cout << "Destructor: " << this->getName() << "\n";
+            }
 
             FileSystem *getParent() const
             {
@@ -380,22 +383,21 @@ namespace
                 // Delete folder should delete all children
                 for (auto f : _children)
                 {
-                    if (f != nullptr)
-                    {
+                        std::cout << "Folder '" << this->getName() << "' deleted : " << f->getName() << "\n";
                         delete f;
-                        f = nullptr;
-                    }
                 }
             }
 
             void add(FileSystem *fs) override
             {
+                std::cout << "Folder '" << this->getName() << "' added : " << fs->getName() << "\n";
                 _children.push_back(fs);
                 fs->setParent(this);
             }
 
             void remove(FileSystem *fs) override
             {
+                std::cout << "Folder: " << this->getName() << "removed : " << fs->getName() << "\n";
                 _children.remove(fs);
                 fs->setParent(nullptr);
             }
@@ -511,23 +513,14 @@ namespace
             root->add(subFolder3);
             Client::clientCode(root);
 
-            // delete file1;
-            // file1 = nullptr;
-
-            // delete file2;
-            // file2 = nullptr;
-
-            // delete file3;
-            // file3 = nullptr;
-
-            // delete subFolder1;
-            // subFolder1 = nullptr;
+            root->remove(file1);
+            delete file1;
 
-            // delete subFolder2;
-            // subFolder2 = nullptr;
+            root->remove(file2);
+            delete file2;
 
-            // delete subFolder3;
-            // subFolder3 = nullptr;
+            root->remove(file3);
+            delete file3;
 
             delete root; // deletes all files/subfolders inside recursively
         }
@@ -541,7 +534,7 @@ struct CompositeAutoRuner
     CompositeAutoRuner()
     {
         std::cout << "\n--- Composite Pattern Example ---\n";
-        Problem::run();
+        // Problem::run();
         CompositePattern::run();
     }
 };