怎么样删除map中指定值为value所有元素？

//第一个解决方案

//erase.h

#include <algorithm>

using std::find_if;

template<class _map>

class Proxy{

typename _map::mapped_type const _value;

public:

Proxy(typename _map::mapped_type const &value):_value(value){}

bool operator()(typename _map::value_type & value){

return value.second==_value;

}

};

template<class _map>

size_t Erase(_map& m,typename _map::mapped_type const &value)

{

size_t count=0;

typename _map::iterator iter;

typename _map::iterator begin=m.begin();

typename _map::iterator end=m.end();

Proxy<_map> proxy(value);

while((iter=find_if(begin,end,proxy))!=end)

{

++count;

m.erase(iter);

begin=m.begin();

end=m.end();

}

return count;

}

//示例代码

#include <string>

#include <map>

#include "erase.h"

using std::map;

using std::string;

typedef map<int ,string> Int2Str;

int main(){

Int2Str sample;

sample[1]=string("abc");

sample[2]=string("abc");

sample[3]=string("1234");

sample[4]=string("abc");

Erase(sample,string("abc"));

return 0;

}

//******************************************************************//

//第二种方法

#include <map>

#include <string>

#include <algorithm>

#include<iostream>

using std::map;

using std::string;

using std::find_if;

using std::endl;

using std::cout;

template <class _MAP>

class DeleteAllValueProxy{

typedef typename _MAP::mapped_type const map_type;

typedef typename _MAP::iterator map_iter;

typedef typename _MAP::const_reference map_value;

map_type _val;

public:

DeleteAllValueProxy(_MAP &rmap,map_type &val)

:_val(val)

{

map_iter begin=rmap.begin();

map_iter end=rmap.end();

map_iter iter=find_if(begin,end,*this);

while (iter!=end)

{

cout<<iter->first<<" "<<iter->second<<endl;

begin=rmap.erase(iter);

end=rmap.end();

iter=find_if(begin,end,*this);

}

}

bool operator()(map_value item){

return item.second==_val;

}

};

template <class _MAP>

inline void DeleteAllValue(_MAP&rmap,typename _MAP::mapped_type const&val)

{

(DeleteAllValueProxy<_MAP>(rmap,val));

}

int main()

{

map<int,string> Int2Str;

Int2Str[5]="abc";

Int2Str[12]="abc";

Int2Str[43]="abc";

Int2Str[27]="abc";

Int2Str[1]="def";

Int2Str[8]="ghi";

Int2Str[24]="jkl";

Int2Str[56]="mn";

Int2Str[0]="opq";

DeleteAllValue(Int2Str,string("abc"));

return 0;

}

//*******************************************************************/

//第三种方法

#include <iostream>