adding the shallow copy example

lectures/08_vector_implementation/vec_shallow_copy.h

@@ -0,0 +1,79 @@
+template<class T>
+class Vec{
+public:
+    // default constructor
+    Vec(){
+        m_data = new T[2];
+	m_size = 0;
+	capacity = 2;
+    }
+
+    // other constructor
+    Vec(int size, const T& val){
+        m_data = new T[size];
+	m_size = size;
+	capacity = size;
+	for(int i=0;i<size;i++){
+	    m_data[i] = val;
+	}
+    }
+
+    // copy constructor
+    /*Vec(const Vec& other){
+        capacity = other.capacity;
+	m_size = other.m_size;
+        m_data = new T[capacity];
+	for(unsigned int i=0;i<m_size;i++){
+            m_data[i] = other.m_data[i];
+	}
+    }*/
+
+    // destructor
+    ~Vec(){
+        delete [] m_data;
+    }
+
+    // assignment operator
+    Vec<T>& operator=(const Vec& other){
+        if(this != &other){
+            capacity = other.capacity;
+	    m_size = other.m_size;
+	    m_data = new T[m_size];
+	    for(unsigned int i=0;i<m_size;i++){
+                m_data[i] = other.m_data[i];
+	    }
+	}
+	return *this;
+    }
+
+    // [] operator
+    T& operator[](int i){
+	return m_data[i];
+    }
+
+    unsigned int size(){
+	    return m_size;
+    }
+
+    void push_back(const T& val){
+	    if(m_size >= capacity){
+                capacity = capacity * 2;
+		// allocate memory for the new array and move content of m_data to the new array.
+                T* temp = new T[capacity];
+		for(unsigned int i=0;i<m_size;i++){
+                    temp[i] = m_data[i];
+		}
+		delete [] m_data;
+		m_data = temp;
+	    }
+	    m_data[m_size] = val;
+            m_size++;
+    }
+    void pop_back(){
+        m_size--;
+    }
+private:
+    int capacity;
+    int m_size;
+    T* m_data;
+};