C++17 STL Cookbook

How it works...

Consider that we write the following code:

for (auto x : range) { code_block; }

The compiler will evaluate it to the following:

{     auto __begin = std::begin(range);    auto __end   = std::end(range);    for ( ; __begin != __end; ++__begin) {         auto x = *__begin;         code_block    } }

While looking at this code, it becomes obvious that the only requirements for the iterators are the following three operators:

• operator!=: unequal comparison
• operator++: prefix increment
• operator*: dereference

The requirements of the range are that it has a begin and an end method, which return two iterators that denote the beginning and the end of a range.

In this book, we're mostly using std::begin(x) instead of x.begin(). This is generally a good style ...