hash_map::operator(STL/CLR)

 

For the latest documentation on Visual Studio 2017, see Visual Studio 2017 Documentation.

Maps a key to its associated mapped value.

mapped_type operator[](key_type key);  

Parameters

key
Key value to search for.

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.

// 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]  

Header: <cliext/hash_map>

Namespace: cliext

hash_map (STL/CLR)
hash_map::find (STL/CLR)
hash_map::insert (STL/CLR)

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