C++ primer中的一道习题（16.12）,该怎么处理

C++ primer中的一道习题（16.12）
题目：
编写一个函数模版，接受表示未知类型迭代器的一对值，找出在序列中出现的最频繁的值。

该如何定义迭代器？

//16.12
#include<iostream>
#include<string>
#include<vector>
#include<list>
using namespace std;

template<typename T, typename V>
V most_occurs(typename T::const_iterator beg, typename T::const_iterator end)
{
typename T::size_type sz=0,max=0;
V tmp;
for(typename T::const_iterator it=beg; it!=end; ++it)
{
sz=count(beg,end,*it);
if(sz>max)
{
max=sz;
tmp=*it;
}
}

return tmp;
}

int main()
{
vector<int> vec;
int i;
for(i=0;i<10;++i)
vec.push_back(i);
vec.push_back(2);
vec.push_back(2);
vector<int>::const_iterator beg=vec.begin(), end=vec.end();
cout<<most_occurs(beg,end )<<endl;
return 0;
}

错误信息如下：
error C2783: 'V __cdecl most_occurs(generic-type-311,generic-type-312)' : could not deduce template argument for 'T'
error C2783: 'V __cdecl most_occurs(generic-type-311,generic-type-312)' : could not deduce template argument for 'V'

请问各位高手该如何定义该template？谢谢^_^

[解决办法]

C/C++ code

#include <iostream> #include <string> #include <vector> #include <iterator>#include <algorithm>#include <list> using   namespace   std; template <typename   T>typename  iterator_traits<T>::value_type most_occurs(   T  beg, T end ){    typename   iterator_traits<T>::difference_type   sz = 0,max = 0;     typename  iterator_traits<T>::value_type tmp;     for ( T  it = beg; it != end; ++it )    {        sz = count( beg, end, *it );         if ( sz > max )        {            max = sz;             tmp = *it;        }    }     return   tmp;} int main(){    vector <int> vec;     int i;     for ( i = 0; i < 10; ++i )    {        vec.push_back( i );    }     vec.push_back( 2 );     vec.push_back( 2 );     vector <int> ::const_iterator   beg = vec. begin(), end = vec.end();     cout << most_occurs( beg, end ) << endl;     return   0;}
[解决办法]
C/C++ code
template <typename T>typename T::value_type mostFre(T first,T last){    allocator<typename T::value_type>alloc;    T newFirst=alloc.allocate(last-first);    T newLast =newFirst +(last-first);    std::uninitialized_copy(first,last,newFirst);    std::sort (newFirst,newLast);    std::size_t maxOccu =0,occ=0;    T preIter =newFirst,maxOccuElemIt =newFirst;    while(newFirst!=newLast)    {        if(*newFirst!=*preIter)        {            if(occu>maxOccu)            {                maxOccu=occu;                maxOccuElemIt=preIter;            }            occu=0;        }        ++occu;        preIter=newFirst;        ++newFirst;    }    if(occu>maxOccu)    {        maxOccu=occu;        maxOccuElemIt=preIter;    }    return *maxOccuElemIt;}
[解决办法]
最简单的做法:cout <<most_occurs<vector<int>,int>(beg,end) <<endl;  呵呵...
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