我有下面的C++代碼,這是我從谷歌的sparsehash網站有:C++:爲什麼不能編譯?
#include <iostream>
#include <google/dense_hash_map>
#include <string.h>
using google::dense_hash_map; // namespace where class lives by default
using std::cout;
using std::endl;
using ext::hash; // or __gnu_cxx::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(void){
dense_hash_map<const char*, int, hash<const char*>, eqstr> months;
months.set_empty_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;
}
,我發現了以下錯誤:
using ext::hash
'分機' 尚未聲明
dense_hash_map<const char*, int, hash<const char*>, eqstr> months;
- '散' 在此範圍未聲明
- 模板參數3是前無效
- 預期不合格的ID '' 令牌
- 預期初始化之前 '>' 令牌
and months.set_empty_key(NULL);
「月」在此範圍
未聲明我是一個有點C++小白和希望有人能指出我在正確的方向。
提前許多感謝,
您是否包含ext庫的頭文件? #include或其他一些庫文件頭丟失 –
QuentinUK