CareerCup

using the initializer list is faster. can be optimized by the compiler better I believe

Not exactly sure of the performance impact by using member initalizer syntax for built in data types. But in the case of Objects(i mean composition.. i composed in the class), the first one is faster, since, in case 1, the object is created by invoking the copy constructor where as in case 2, the object i is initially created using the default constructor, then initialised using the copy constructor.

For built in data types, something like this
int i
i =j

int i=j

For objects.
Object i(j)

Object i;
i=j;

I guess this answers your question

Thanks
RaghuC

For built-in type data, they will not be implicitly initialized in the initialization phase. So, the performance is equivalent when they are initialized in the initialization list or the constructor functions body.

Initialiser list initialization is faster.
Reason:It initialise 'i' using copy constructor.(one function call)
In the other case ,i constructor is called then a assignment operator is called again to assign..(two function calls)

found this in one website:

class Qux
{
        public:
                Qux() : _foo( "initialize foo to this!" ) { }
                // This is nearly equivalent to 
                // Qux() { _foo = "initialize foo to this!"; }
                // but without the extra call to construct an empty string

        private:
        std::string _foo;
};

So i guess initialization Lists is faster because, it wont call constructor for int( ); and then the operator i=j;
It will directly call i(j);