Using tuple in unordered_map

The template arguments for an unordered_map looks like this:

template<

    class Key,
    class T,
    class Hash = std::hash<Key>,
    class KeyEqual = std::equal_to<Key>,
    class Allocator = std::allocator< std::pair<const Key, T> >
> class unordered_map;

std::hash is not specialized for tuples (scroll down to Standard specializations for library types). Therefore you need to provide your own, something like this:

typedef std::tuple<int, char, char> key_t;

struct key_hash : public std::unary_function<key_t, std::size_t>
{
 std::size_t operator()(const key_t& k) const
 {
   return std::get<0>(k) ^ std::get<1>(k) ^ std::get<2>(k);
 }
};
// ..snip..
typedef std::unordered_map<const key_t,data,key_hash,key_equal> map_t;
//                                             ^ this is our custom hash

And finally, as Benjamin Lindley answer already addresses, you need to use std::make_tuple:

// d is data
m[std::make_tuple(1, 'a', 'b')] = d;
auto itr = m.find(std::make_tuple(1, 'a', 'b'));

The code was grabbed from Using a std::tuple as key for std::unordered_map and here is the Live Example.

First error:

map.cpp:9:21: error:   expected a type, got ‘kk’

As the error clearly says, the template parameter needs to be a type. kk is not a type, it is an object. Perhaps you meant to make it a typedef?

typedef tuple <int,char,char> kk;
unordered_map<kk,int> map;

Second error:

map[1,"c","b"]=23;

Two problems here. First, putting commas between values does not make a tuple out of them. You need to be explicit about it, either calling the constructor of your tuple type, or using a function which returns a tuple (e.g. std::make_tuple). Second, your tuple is expecting chars ('c','b'), not strings ("c","b").

map[std::make_tuple(1,'c','b')] = 23;

I had a requirement of map instead of unordered map:
key was 3-tuple and
value was a 4-tuple

seeing all answers, I was about to change to pairs

but, below worked for me:

// declare a map called map1
map <
  tuple<short, short, short>,
  tuple<short, short, short, short>
> map1;

// insert an element into map1
map1[make_tuple(1, 1, 1)] = make_tuple(0, 0, 1, 1);

// this also worked
map1[{1, 1, 1}] = { 0, 0, 1, 1 };

I am using visual studio community 2015 ide

As pointed out, std::hash is not specialized for tuples. However, if your tuple consists of standard hashable types like string and int, the following code from generic-hash-for-tuples-in-unordered-map-unordered-set will automatically add such support in c++11.

Just paste the code in a header file and include it whenever needed:

#include <tuple>
// function has to live in the std namespace 
// so that it is picked up by argument-dependent name lookup (ADL).
namespace std{
    namespace
    {

        // Code from boost
        // Reciprocal of the golden ratio helps spread entropy
        //     and handles duplicates.
        // See Mike Seymour in magic-numbers-in-boosthash-combine:
        //     https://stackoverflow.com/questions/4948780

        template <class T>
        inline void hash_combine(std::size_t& seed, T const& v)
        {
            seed ^= hash<T>()(v) + 0x9e3779b9 + (seed<<6) + (seed>>2);
        }

        // Recursive template code derived from Matthieu M.
        template <class Tuple, size_t Index = std::tuple_size<Tuple>::value - 1>
        struct HashValueImpl
        {
          static void apply(size_t& seed, Tuple const& tuple)
          {
            HashValueImpl<Tuple, Index-1>::apply(seed, tuple);
            hash_combine(seed, get<Index>(tuple));
          }
        };

        template <class Tuple>
        struct HashValueImpl<Tuple,0>
        {
          static void apply(size_t& seed, Tuple const& tuple)
          {
            hash_combine(seed, get<0>(tuple));
          }
        };
    }

    template <typename ... TT>
    struct hash<std::tuple<TT...>> 
    {
        size_t
        operator()(std::tuple<TT...> const& tt) const
        {                                              
            size_t seed = 0;                             
            HashValueImpl<std::tuple<TT...> >::apply(seed, tt);    
            return seed;                                 
        }                                              

    };
}