add()

template<typename type_t , typename allocator_t = xtd::collections::generic::helpers::allocator<typename std::conditional<std::is_same<bool, type_t>::value, char, type_t>::type>>

void xtd::collections::generic::list< type_t, allocator_t >::add ( const type_t &  item )

inlineoverridevirtual

Adds an object to the end of the xtd::collections::generic::list <type_t>.

Parameters

item

The object to be added to the end of the xtd::collections::generic::list <type_t>. @)ar Examples The following example demonstrates how to add, remove, and insert a simple business object in a xtd::collections::generic::list <type_t>. #include <xtd/xtd> using namespace xtd; using namespace xtd::collections::generic; // Simple business object. A part_id is used to identify the type of part // but the part name can change. class part : public object, public iequatable<part> { public: string part_name; int part_id = 0; part() = default; part(const string& name, int id) : part_name {name}, part_id {id} {} string to_string() const noexcept override {return string::format("ID: {} Name: {}", part_id, part_name);} bool equals(const object& obj) const noexcept override {return is<part>(obj) && equals(as<part>(obj));} bool equals(const part& other) const noexcept override {return part_id == other.part_id;} size get_hash_code() const noexcept override {return part_id;} }; class example { public: static auto main() -> void { // Create a list of parts. auto parts = list<part>(); // Add parts to the list. parts.add(part {"crank arm", 1234}); parts.add(part {"chain ring", 1334}); parts.add(part {"regular seat", 1434}); parts.add(part {"banana seat", 1444}); parts.add(part {"cassette", 1534}); parts.add(part {"shift lever", 1634}); // Write out the parts in the list. This will call the overridden ToString method // in the part class. console::write_line(); for (auto part : parts) console::write_line(part); // Check the list for part #1734. This calls the iequatable::equals method of the part class, which checks the partId for equality. console::write_line("\ncontains(\"1734\"): {0}", parts.contains(part {"", 1734})); // Insert a new item at position 2. console::write_line("\nInsert(2, \"1834\")"); parts.insert(2, part {"brake lever", 1834}); //console::write_line(); for (auto part : parts) console::write_line(part); console::write_line("\nparts[3]: {0}", parts[3]); console::write_line("\nremove(\"1534\")"); // This will remove part 1534 even though the partName is different, because the equals method only checks part_id for equality. parts.remove(part {"cogs", 1534}); console::write_line(); for (auto part : parts) console::write_line(part); console::write_line("\nremove_at(3)"); // This will remove the part at index 3. parts.remove_at(3); console::write_line(); for (auto part : parts) console::write_line(part); } }; startup_(example::main); // This code produces the following output : // // // ID: 1234 Name: crank arm // ID: 1334 Name: chain ring // ID: 1434 Name: regular seat // ID: 1444 Name: banana seat // ID: 1534 Name: cassette // ID: 1634 Name: shift lever // // contains("1734"): false // // Insert(2, "1834") // ID: 1234 Name: crank arm // ID: 1334 Name: chain ring // ID: 1834 Name: brake lever // ID: 1434 Name: regular seat // ID: 1444 Name: banana seat // ID: 1534 Name: cassette // ID: 1634 Name: shift lever // // parts[3]: ID: 1434 Name: regular seat // // remove("1534") // // ID: 1234 Name: crank arm // ID: 1334 Name: chain ring // ID: 1834 Name: brake lever // ID: 1434 Name: regular seat // ID: 1444 Name: banana seat // ID: 1634 Name: shift lever // // remove_at(3) // // ID: 1234 Name: crank arm // ID: 1334 Name: chain ring // ID: 1834 Name: brake lever // ID: 1444 Name: banana seat // ID: 1634 Name: shift lever The following example demonstrates several properties and methods of the xtd::collections::generic::list <type_t> generic class, including the xtd::collections::generic::list::add method. The parameterless constructor is used to create a list of strings with a capacity of 0. The xtd::collections::generic::list::capacity property is displayed, and then the xtd::collections::generic::list::add method is used to add several items. The items are listed, and the xtd::collections::generic::list::capacity property is displayed again, along with the xtd::collections::generic::list::count property, to show that the capacity has been increased as needed.

Other properties and methods are used to search for, insert, and remove elements from the list, and finally to clear the list.

#include <xtd/xtd>
 
using namespace xtd;
using namespace xtd::collections::generic;
 
class example {
public:
  static auto main() -> void {
    auto dinosaurs = list<string> {};
    
    console::write_line("\ncapacity: {0}", dinosaurs.capacity());
    
    dinosaurs.add("Tyrannosaurus");
    dinosaurs.add("Amargasaurus");
    dinosaurs.add("Mamenchisaurus");
    dinosaurs.add("Deinonychus");
    dinosaurs.add("Compsognathus");
    console::write_line();
    for (auto dinosaur : dinosaurs)
      console::write_line(dinosaur);
    
    console::write_line("\ncapacity: {0}", dinosaurs.capacity());
    console::write_line("count: {0}", dinosaurs.count());
    
    console::write_line("\ncontains(\"Deinonychus\"): {0}", dinosaurs.contains("Deinonychus"));
    
    console::write_line("\ninsert(2, \"Compsognathus\")");
    dinosaurs.insert(2, "Compsognathus");
    
    console::write_line();
    for (auto dinosaur : dinosaurs)
      console::write_line(dinosaur);
    
    // Shows accessing the list using the Item property.
    console::write_line("\ndinosaurs[3]: {0}", dinosaurs[3]);
    
    console::write_line("\nremove(\"Compsognathus\")");
    dinosaurs.remove("Compsognathus");
    
    console::write_line();
    for (auto dinosaur : dinosaurs)
      console::write_line(dinosaur);
    
    dinosaurs.trim_excess();
    console::write_line("\ntrim_excess()");
    console::write_line("capacity: {0}", dinosaurs.capacity());
    console::write_line("count: {0}", dinosaurs.count());
    
    dinosaurs.clear();
    console::write_line("\nclear()");
    console::write_line("capacity: {0}", dinosaurs.capacity());
    console::write_line("count: {0}", dinosaurs.count());
  }
};
 
startup_(example::main);
 
// This code produces the following output :
//
// capacity: 0
//
// Tyrannosaurus
// Amargasaurus
// Mamenchisaurus
// Deinonychus
// Compsognathus
//
// capacity: 8
// count: 5
//
// contains("Deinonychus"): true
//
// insert(2, "Compsognathus")
//
// Tyrannosaurus
// Amargasaurus
// Compsognathus
// Mamenchisaurus
// Deinonychus
// Compsognathus
//
// dinosaurs[3]: Mamenchisaurus
//
// remove("Compsognathus")
//
// Tyrannosaurus
// Amargasaurus
// Mamenchisaurus
// Deinonychus
// Compsognathus
//
// trim_excess()
// capacity: 5
// count: 5
 
// clear()
// capacity: 5
// count: 0

Remarks

xtd::collections::generic::list <type_t> allows duplicate elements.

If xtd::collections::generic::list::count already equals xtd::collections::generic::list::capacity, the capacity of the xtd::collections::generic::list <type_t> is increased by automatically reallocating the internal array, and the existing elements are copied to the new array before the new element is added.

If xtd::collections::generic::list::count is less than xtd::collections::generic::list::capacity, this method is an O(1) operation. If the capacity needs to be increased to accommodate the new element, this method becomes an O(n) operation, where n is xtd::collections::generic::list::count.

Implements xtd::collections::generic::icollection< type_t >.