Question

I have this question that runs in my mind…
I have a std::vector to iterate:
which is the best way (the faster) to iterate?

here is the code using an iterator:

// using the iterator
for( std::vector <myClass*>::iterator it = myObject.begin( ); it != myObject.end( ); it++ )
{
    (*it)->someFunction( );
}

and here is ‘normal’ mode…

// normal loop
for( int i = 0; i < myObject.Size( ); i++ )
{
    myObject[i]->someFunction( );
}

thanks for your suggestions!

Answer 1

None of the two will be any faster really, because on most implementations a vector<T>::iterator is just a typedef for T* and size is cached.

But doing ++it instead of it++ is a good habit. The latter involves creating a temporary.

for(std::vector <myClass*>::iterator it = myObject.begin( );
                           it != myObject.end( );
                           ++it)
                           ^^^^  

On other containers such as map, list etc. with nontrivial iterators the difference between postincrement and preincrement might become noticable.