大龍的博客

岳不群－華山派掌門人，人稱君子劍
張三豐－武當(dāng)掌門人，太極拳創(chuàng)始人
東方不敗－第一高手，葵花寶典
...

#include <map>
#include <string>
using namespace std;
...
map<string, string> namemap;
//增加。。。
namemap["岳不群"]="華山派掌門人，人稱君子劍";
namemap["張三豐"]="武當(dāng)掌門人，太極拳創(chuàng)始人";
namemap["東方不敗"]="第一高手，葵花寶典";
...
//查找。。
if(namemap.find("岳不群") != namemap.end()){
...
}

#include <hash_map>
#include <string>
using namespace std;
int main(){
hash_map<int, string> mymap;
mymap[9527]="唐伯虎點(diǎn)秋香";
mymap[1000000]="百萬(wàn)富翁的生活";
mymap[10000]="白領(lǐng)的工資底線";
...
if(mymap.find(10000) != mymap.end()){
...
}

template <class _Key, class _Tp, class _HashFcn = hash<_Key>,
class _EqualKey = equal_to<_Key>,
class _Alloc = __STL_DEFAULT_ALLOCATOR(_Tp) >
class hash_map
{
...
}

...
hash_map<int, string> mymap;
//等同于:
hash_map<int, string, hash<int>, equal_to<int> > mymap;

struct hash<int> {
size_t operator()(int __x) const { return __x; }
};

struct hash<char*>
struct hash<const char*>
struct hash<char>
struct hash<unsigned char>
struct hash<signed char>
struct hash<short>
struct hash<unsigned short>
struct hash<int>
struct hash<unsigned int>
struct hash<long>
struct hash<unsigned long> 

struct str_hash{
size_t operator()(const string& str) const
{
unsigned long __h = 0;
for (size_t i = 0 ; i < str.size() ; i ++)
__h = 5*__h + str[i];
return size_t(__h);
}
};
//如果你希望利用系統(tǒng)定義的字符串hash函數(shù)，你可以這樣寫：
struct str_hash{
size_t operator()(const string& str) const
{
return return __stl_hash_string(str.c_str());
}
};

map<string, string> namemap;
//改為：
hash_map<string, string, str_hash> namemap;

//本代碼可以從SGI STL
//先看看binary_function 函數(shù)聲明，其實(shí)只是定義一些類型而已。
template <class _Arg1, class _Arg2, class _Result>
struct binary_function {
typedef _Arg1 first_argument_type;
typedef _Arg2 second_argument_type;
typedef _Result result_type;
};
//看看equal_to的定義：
template <class _Tp>
struct equal_to : public binary_function<_Tp,_Tp,bool>
{
bool operator()(const _Tp& __x, const _Tp& __y) const { return __x == __y; }
};

struct mystruct{
int iID;
int  len;
bool operator==(const mystruct & my) const{
return (iID==my.iID) && (len==my.len) ;
}
};  

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

typedef hash_map<const char*, string, hash<const char*>, compare_str> StrIntMap;
StrIntMap namemap;
namemap["岳不群"]="華山派掌門人，人稱君子劍";
namemap["張三豐"]="武當(dāng)掌門人，太極拳創(chuàng)始人";
namemap["東方不敗"]="第一高手，葵花寶典";

-bash-2.05b$ cat my.cpp
#include <hash_map>
#include <string>
#include <iostream>
using namespace std;
//define the class
class ClassA{
public:
ClassA(int a):c_a(a){}
int getvalue()const { return c_a;}
void setvalue(int a){c_a;}
private:
int c_a;
};
//1 define the hash function
struct hash_A{
size_t operator()(const class ClassA & A)const{
//  return  hash<int>(classA.getvalue());
return A.getvalue();
}
};
//2 define the equal function
struct equal_A{
bool operator()(const class ClassA & a1, const class ClassA & a2)const{
return  a1.getvalue() == a2.getvalue();
}
};
int main()
{
hash_map<ClassA, string, hash_A, equal_A> hmap;
ClassA a1(12);
hmap[a1]="I am 12";
ClassA a2(198877);
hmap[a2]="I am 198877";
cout<<hmap[a1]<<endl;
cout<<hmap[a2]<<endl;
return 0;
}
-bash-2.05b$ make my
c++  -O -pipe -march=pentiumpro  my.cpp  -o my
-bash-2.05b$ ./my
I am 12
I am 198877