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c++arraysstdstdarray

Whats the point of .begin() and .end()?

In C++ library arrays, what are some cases where it's useful to have the .begin() and .end() member functions?

On cplusplus.com, the example use is to iterate through an array:

for ( auto it = myarray.begin(); it != myarray.end(); ++it )

But 

for (int i = 0; i < myarray.size(); i++)

can be used for that.

Solution

  • begin() and end() return iterators. Iterators provide uniform syntax to access different types of containers. At the first glance they might look like an overkill for traversing a simple array, but consider that you could write the same code to traverse a list, or a map.

    This uniform access to various containers will allow you to write algorithms that work on all of them without knowing their internal structure. A for loop from begin to end is just a first piece in a much larger mosaic. Just look up the list of standard algorithms to appreciate the power of this simple abstraction.