跟编译器有关？

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<iterator>   
using namespace std;
template <typename T>typename T::value_type mostFre(T first,T last){
    std::size_t amount=0;
    T start=first;
    while(start!=last){
        amount++;
        start++;
    }
typedef  std::vector<typename T::value_type>VecType;
VecType vec(amount);
VecType::iterator newFirst=vec.begin();
VecType::iterator newlLast=vec.end();
std::uninitialized_copy(first,last,newFirst);
std::sort(newFirst,newlLast);
std::size_t maxOccu=0,occu=0;
VecType::iterator preIter=newFirst;
VecType::iterator maxOccuElmIt=newFirst;
while(newFirst!=newLast){
    if(*newFirst!=*preIter){
        if(occu>maxOccu){
            maxOccu=occu;
            maxOccuElmIt=preIter;
        }
        occu=0;
    }++occu;
    preIter=newFirst;
++newFirst;
}

if(occu>maxOccu){
    maxOccu=occu;
    maxOccuElmIt=preIter;
}
return *maxOccuElmIt;

}
int main(){
        int ia[]={
                1 ,2,3, 4, 5, 1,2,3,1,7
        };
        vector<int>ve(ia,ia+10);
        vector<int>::iterator a=ve.begin(),b=ve.end();
        cout<<mostFre(a,b)<<endl;
        return 0;
}