stl algorithm in class

Question

Is there a way to use stl algorithms like find() and find_if() in a container of objects? Ex.:With find() find the element whit name "abc" in a vector of class Alfhabetic.

Answer 1

You can define a comparing predicate (functor). Here is a generic implementation:

struct AlphabeticNameComp
{
   AlphabeticNameComp( const std::string& toCompare)
      : toCompare_( toCompare) { }

   bool operator()( const Alphabetic& obj) const
   {
       return toCompare_ == obj.name();
   }

private:
   const std::string toCompare_;
};

In a vector of Alphabetic elements

std::vector< Alphabetic> vect;

you can run a search like:

std::find_if( vect.begin(), vect.end(), AlphabeticNameComp( "abc"));

Answer 2

You can define an operator==() for class Alfhabetic that matches only the data member abc

something like that:

bool operator==(const Alfhabetic& a, const Alfhabetic& b)
{
    return (a.abc == b.abc);
}

and then finding an Alfhabetic instance initialized with abc as the value you want.