hash_map::operator[] (STL/CLR)
Maps a key to its associated mapped value.
mapped_type operator[](key_type key);
Parameters
- key
Key value to search for.
Remarks
The member functions endeavors to find an element with equivalent ordering to key. If it finds one, it returns the associated mapped value; otherwise, it inserts value_type(key, mapped_type()) and returns the associated (default) mapped value. You use it to look up a mapped value given its associated key, or to ensure that an entry exists for the key if none is found.
Example
// cliext_hash_map_operator_sub.cpp
// compile with: /clr
#include <cliext/hash_map>
typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
{
Myhash_map c1;
c1.insert(Myhash_map::make_value(L'a', 1));
c1.insert(Myhash_map::make_value(L'b', 2));
c1.insert(Myhash_map::make_value(L'c', 3));
// display contents " [a 1] [b 2] [c 3]"
for each (Myhash_map::value_type elem in c1)
System::Console::Write(" [{0} {1}]", elem->first, elem->second);
System::Console::WriteLine();
System::Console::WriteLine("c1[{0}] = {1}",
L'A', c1[L'A']);
System::Console::WriteLine("c1[{0}] = {1}",
L'b', c1[L'b']);
// redisplay altered contents
for each (Myhash_map::value_type elem in c1)
System::Console::Write(" [{0} {1}]", elem->first, elem->second);
System::Console::WriteLine();
// alter mapped values and redisplay
c1[L'A'] = 10;
c1[L'c'] = 13;
for each (Myhash_map::value_type elem in c1)
System::Console::Write(" [{0} {1}]", elem->first, elem->second);
System::Console::WriteLine();
return (0);
}
[a 1] [b 2] [c 3]
c1[A] = 0
c1[b] = 2
[a 1] [A 0] [b 2] [c 3]
[a 1] [A 10] [b 2] [c 13]
Requirements
Header: <cliext/hash_map>
Namespace: cliext