hash_map
Always there is problems with a hash_map, but google has a solution:
You must install "sparsehash" (apt-get install sparsehash)
The documentation is here:
http://goog-sparsehash.sourceforge.net/
And here there is an example:
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#include <iostream>
#include <google/sparse_hash_map>
using google::sparse_hash_map; // namespace where class lives by default
using std::cout;
using std::endl;
using __gnu_cxx::hash; // or ext::hash, or maybe tr1::hash, depending on your OS
struct eqstr
{
bool operator()(const char* s1, const char* s2) const
{
return (s1 == s2) || (s1 && s2 && strcmp(s1, s2) == 0);
}
};
int main()
{
sparse_hash_map<const char*, int, hash<const char*>, eqstr> months;
sparse_hash_map<const char*, int, hash<const char*>, eqstr>::iterator It;
months.set_deleted_key(NULL);
months["january"] = 31;
months["february"] = 28;
months["march"] = 31;
months["april"] = 30;
months["may"] = 31;
months["june"] = 30;
months["july"] = 31;
months["august"] = 31;
months["september"] = 30;
months["october"] = 31;
months["november"] = 30;
months["december"] = 31;
cout << "september -> " << months["september"] << endl;
cout << "april -> " << months["april"] << endl;
cout << "june -> " << months["june"] << endl;
cout << "november -> " << months["november"] << endl;
/* Find and erase */
It = months.find("january");
if (It != months.end())
{
cout << "january found" << endl;
cout << "erasing january" << endl;
months.erase(It);
if (months.find("january") == months.end())
cout << "january erased" << endl;
else
cout << "january NOT erased" << endl;
}
else
cout << "january NOT found" << endl;
return 0;
}
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