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

See Also

Reference

hash_map (STL/CLR)

hash_map::find (STL/CLR)

hash_map::insert (STL/CLR)