nlohmannjson/docs/begin.md

iterator begin();
const_iterator begin() const;
const_iterator cbegin() const;

Description

Returns an iterator to the first value in the JSON container. If the JSON container is empty, the returned iterator will be equal to end().

Parameters

None.

Return value

Iterator to the first value. Note the return value its deferencabilty depends on the different value types:

value type	deferenceable	description
null	no	null has no value, always equal to end()
boolean	yes	iterator to the boolean value
string	yes	iterator to the string value
number	yes	iterator to the number value
object	only if object is not empty	iterator to the begin of the object
array	only if array is not empty	iterator to the begin of the array

Complexity

Constant, as long as ArrayType and ObjectType satisfy the Container concept.

Exceptions

None. The function's noexcept-specification is noexcept.

See also

• end, cend
  returns an iterator to the end