These are the member initialiser lists not only used for the syntax also for the performance of not creating other non wanted object

Member initialiser lists/Log.cpp

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+#include <iostream>
+#include <string>
+
+class Example
+{
+    public :
+      Example()
+      {
+        std::cout << "Created Entity!" << std::endl;
+
+      }
+
+      Example(int x)
+      {
+
+        std::cout << "Created Entity with " << x << "!" << std::endl;
+
+      }
+
+};
+
+class Entity
+{
+           //This is through member initializer list!!
+    private :
+       std::string m_Name;
+       Example m_Example;//created an Entity! like it  is in Entity class
+
+
+       //int m_Score;
+       //int x, y, z;
+
+     public :
+
+     Entity() 
+               : m_Example(Example(8)) //we can also use only 8 inside
+                //:  x(0), y(0), z(0)//,m_Score(0) //Initialiser list need to list in order of class members declared!!
+     {
+        //m_Name = "Unknown";//ThiS m_Name object constructed twice [default constrfuctor and with unknown parameter]
+
+            m_Name = std::string("Unknown");
+            //m_Example = Example(8);
+
+     }
+
+     Entity(const std::string& name)  //constructor
+                : m_Name(name)
+     {
+     }
+         const std::string& GetName() const {
+            return m_Name;
+         }
+
+};
+
+int main()
+{
+
+    Entity e0;
+     //std::cout << e0.GetName() << std::endl;
+
+    /*Entity e1("Cherno");
+     std::cout << e1.GetName() << std::endl;*/
+
+    std::cin.get();
+}
+
+     //this keeps code in the constructor a lot cleaner !!
+     //but there is funtional differnce specifically applied to classes

Member initialiser lists/main.cpp

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+//Its a way for us to initialiaze our class member funtions in the constructor
+
+#include <iostream>
+#include <string>
+
+class Entity
+{
+
+    private :
+       std::string m_Name;
+     public :
+
+     Entity() //Default constructor 
+     {
+            m_Name = "Unknown";
+     }
+
+     Entity(const std::string& name)  //constructor
+     {
+           m_Name = name;
+
+     }
+         const std::string& GetName() const {
+            return m_Name;
+         }
+
+};
+
+int main()
+{
+
+    Entity e0;
+     std::cout << e0.GetName() << std::endl;
+
+    Entity e1("Cherno");
+     std::cout << e1.GetName() << std::endl;
+
+    std::cin.get();
+}