Printing all the permutations of a string in alphabetical order-ver1.1
Nothing I would bother about complaing about in real code review.

But for argument's sake:

Pass by const ref

Rather than passing by value. It usually means that an extra copy will be removed. In this case that's not true but I think its a good habit.

void readInputFile( std::string const&amp; filename ) 


No need to return 0 from main

If main() can not return anything else. Then I don't bother with a return statement in main (it's special). The compiler adds a return 0 if no return is provided for main.

Personally I use this (that face that I have not added a return) to indicate that the application has no real failure state.