push_back.md

jsoncons::basic_json::push_back

template <typename T>
void push_back(T&& val)

Adds a new json element at the end of a json array. The argument val is forwarded to the json constructor as std::forward<T>(val). Throws std::domain_error if not an array.

Examples

Creating an array of elements

json cities(json_array_arg);       // an empty array
std::cout << cities << '\n';  // output is "[]"

cities.push_back("Toronto");  
cities.push_back("Vancouver");
// Insert "Montreal" at beginning of array
cities.insert(cities.array_range().begin(),"Montreal");  

std::cout << cities << '\n';

Output:

[]
["Montreal","Toronto","Vancouver"]

Creating an array of elements with reserved storage

json cities(json_array_arg);  
cities.reserve(10);  // storage is reserved
std::cout << "capacity=" << cities.capacity() 
          << ", size=" << cities.size() << '\n';

cities.push_back("Toronto");  
cities.push_back("Vancouver");
cities.insert(cities.array_range().begin(),"Montreal");
std::cout << "capacity=" << cities.capacity() 
          << ", size=" << cities.size() << '\n';

std::cout << cities << '\n';

Output:

capacity=10, size=0
capacity=10, size=3
["Montreal","Toronto","Vancouver"]