C++

Forum

 
a problem of using STL ,the hash_map

fanrongqi (14)
My code is like this:

#include <iostream>
#include <algorithm>
#include <hash_map>
#include <string>
struct str_hash{
std::size_t operator()(const std::string& str) const
{
unsigned long __h = 0;
for (std::size_t i = 0 ; i < str.size() ; i ++)
__h = 5*__h + str[i];
return std::size_t(__h);
}
};


struct compare_str{
bool operator()(const char* p1, const char*p2) const{
return strcmp(p1,p2)==0;
}
};

typedef stdext::hash_map<const char*, std::string, str_hash, compare_str> StrIntMap;
//If I don't add the next line code . the program can complied successfully.
//but I can't complied when I add the code: StrIntMap hash_mapme;
StrIntMap hash_mapme;

I complied this code on VS 2005,
What will I do if I want to use hash_map? please give me an example please.
thanks .

PanGalactic (1658)
Please edit your post and put your code inside code tags.
ne555 (10692)
fanrongqi (14)
sorry,this will be ok.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
 
#include <iostream>
 #include <algorithm>
 #include <hash_map>
 #include <string>
 struct str_hash{ 
 std::size_t operator()(const std::string& str) const 
 {
 unsigned long __h = 0; 
 for (std::size_t i = 0 ; i < str.size() ; i ++) 
 __h = 5*__h + str[i]; 
 return std::size_t(__h); 
 } 
 };


 struct compare_str{
 bool operator()(const char* p1, const char*p2) const{
 return strcmp(p1,p2)==0;
 }
 }; 

 typedef stdext::hash_map<const char*, std::string, str_hash, compare_str> StrIntMap;
 //If I don't add the next line code . the program can complied successfully.
 //but I can't complied when I add the code: StrIntMap hash_mapme;
 StrIntMap hash_mapme;
Last edited on
ne555 (10692)
And the compiler error is...

hash_map<Key, Data, HashFcn, EqualKey, Alloc> Just a guess, but ¿shouldn't the HashFcn apply to the key?
In your case const char*
Topic archived. No new replies allowed.