Advantages of std::for_each over for loop

Question

Are there any advantages of std::for_each over for loop? To me, std::for_each only seems to hinder the readability of code. Why do then some coding

Answer 1

You can have the iterator be a call to a function that is performed on each iteration through the loop.

See here: http://www.cplusplus.com/reference/algorithm/for_each/

Answer 2

The nice thing with C++11 (previously called C++0x), is that this tiresome debate will be settled.

I mean, no one in their right mind, who wants to iterate over a whole collection, will still use this

for(auto it = collection.begin(); it != collection.end() ; ++it)
{
   foo(*it);
}

Or this

for_each(collection.begin(), collection.end(), [](Element& e)
{
   foo(e);
});

when the range-based for loop syntax is available:

for(Element& e : collection)
{
   foo(e);
}

This kind of syntax has been available in Java and C# for some time now, and actually there are way more foreach loops than classical for loops in every recent Java or C# code I saw.

Answer 3

The advantage of writing functional for beeing more readable, might not show up when for(...) and for_each(...).

If you utilize all algorithms in functional.h, instead of using for-loops, the code gets a lot more readable;

iterator longest_tree = std::max_element(forest.begin(), forest.end(), ...);
iterator first_leaf_tree = std::find_if(forest.begin(), forest.end(), ...);
std::transform(forest.begin(), forest.end(), firewood.begin(), ...);
std::for_each(forest.begin(), forest.end(), make_plywood);

is much more readable than;

Forest::iterator longest_tree = it.begin();
for (Forest::const_iterator it = forest.begin(); it != forest.end(); ++it{
   if (*it > *longest_tree) {
     longest_tree = it;
   }
}

Forest::iterator leaf_tree = it.begin();
for (Forest::const_iterator it = forest.begin(); it != forest.end(); ++it{
   if (it->type() == LEAF_TREE) {
     leaf_tree  = it;
     break;
   }
}

for (Forest::const_iterator it = forest.begin(), jt = firewood.begin(); 
     it != forest.end(); 
     it++, jt++) {
          *jt = boost::transformtowood(*it);
    }

for (Forest::const_iterator it = forest.begin(); it != forest.end(); ++it{
    std::makeplywood(*it);
}

And that is what I think is so nice, generalize the for-loops to one line functions =)