Calling constructors for the data members of the object of a class results in an overhead process which calls the constructor in the main function. You can reduce this overhead by using member initializers in classes. For example:

 Class A{public:A(int i,int w){a=i;b=w;}private:int a,b;};//INSTEAD WE CAN USE MEMBER INTIALISERS EXAMPLE FOLLOWS Class A{public:A(int i,int w):a(i),a(w){//empty body of constructor }private:int a,b;};

The latter code is better optimized and more efficient.