...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
A value
stores an instance of array
as the underlying representation
for a JSON array. Instances of the array
type function identically
to a std::vector
of value
.
Additionally:
storage_ptr
as the container
itself.
An empty array may be constructed without incurring any memory allocations
using the default memory resource. A storage_ptr
can also be explicitly
specified:
array arr1; // empty array, uses the default memory resource array arr2( make_shared_resource<monotonic_resource>() ); // empty array, uses a counted monotonic resource
Initializer lists can be used to construct objects with initial contents. These constructors may allocate memory and throw:
array arr( { "Hello", 42, true } );
Alternatively, elements may be inserted after construction:
array arr; arr.emplace_back( "Hello" ); arr.emplace_back( 42 ); arr.emplace_back( true );
Similar to its standard library counterpart, elements may be accessed directly
by their 0-based index with bounds checking using at
, or without bounds checking using
operator[]
:
assert( arr[0].as_string() == "Hello" ); // The following line throws std::out_of_range, since the index is out of range arr.at( 3 ) = nullptr;
For the complete listing of all available member functions and nested types,
see the reference page for array
.
When an array
is formatted to a std::ostream
,
the result is a valid JSON. That is, the array will be output with square
brackets and the comma separated list of values, as per the JSON specification.