unordered_map自定义key

struct MAP_KEY {

double first;

double second;

double third;

double forth;

};

struct KeyHash

{

std::size_t operator()(const MAP_KEY & k) const

{

using boost::hash_value;

using boost::hash_combine;

std::size_t seed = 0;

hash_combine(seed,hash_value(k.first));

hash_combine(seed,hash_value(k.second));

hash_combine(seed,hash_value(k.third));

hash_combine(seed,hash_value(k.forth));

return seed;

}

};

struct cmp_fun //比较函数 ==

{

bool operator()( MAP_KEY addr1, MAP_KEY addr2) const {

return ((addr1.first==addr2.first)&&(addr1.second==addr2.second)&&(addr1.third==addr2.third)&&(addr1.forth==addr2.forth));

}

};

static std::tr1::unordered_map<MAP_KEY, double,KeyHash,cmp_fun> Map_Dist;

本来想把四个double转换成char*，发现是个bug，就自己写了个结构体，之后相同的情况可以如此处理。