unordered_map::key_type

The type of an ordering key.

typedef Key key_type;

Remarks

The type is a synonym for the template parameter Key.

Example

 

// std_tr1__unordered_map__unordered_map_key_type.cpp 
// compile with: /EHsc 
#include <unordered_map> 
#include <iostream> 
 
typedef std::unordered_map<char, int> Mymap; 
int main() 
    { 
    Mymap c1; 
 
    c1.insert(Mymap::value_type('a', 1)); 
    c1.insert(Mymap::value_type('b', 2)); 
    c1.insert(Mymap::value_type('c', 3)); 
 
// display contents " [c 3] [b 2] [a 1]" 
    for (Mymap::const_iterator it = c1.begin(); 
        it != c1.end(); ++it) 
        std::cout << " [" << it->first << ", " << it->second << "]"; 
    std::cout << std::endl; 
 
// add a value and reinspect 
    Mymap::key_type key = 'd'; 
    Mymap::mapped_type mapped = 4; 
    Mymap::value_type val = Mymap::value_type(key, mapped); 
    c1.insert(val); 
 
    for (Mymap::const_iterator it = c1.begin(); 
        it != c1.end(); ++it) 
        std::cout << " [" << it->first << ", " << it->second << "]"; 
    std::cout << std::endl; 
 
    return (0); 
    } 
 
 [c, 3] [b, 2] [a, 1]
 [d, 4] [c, 3] [b, 2] [a, 1]

Requirements

Header: <unordered_map>

Namespace: std

See Also

Reference

<unordered_map>

unordered_map Class

unordered_map::mapped_type

unordered_map::value_type