调用的歧义问题，我有点费解。大家指点一下啊，谢谢
#include<algorithm>
#include<iostream>
#include<string>
#include<cstddef>
#include<iterator>
using namespace std;
template<class in ,class out,class pred >void copy_if(in begin,in end,out res,pred p)
{
while(begin!=last)
if(p(*begin)){*res++=*begin;begin++;}
}
bool less_tan10(int d){return d<10;}
int main()
{
int a[]={12,21,2,13,1,214,345,2,232,5};
const size_t SIZE=sizeof a/sizeof a[0];
copy_if(a,a+SIZE,ostream_iterator<int>(cout,"\n"),less_tan10);//这里调用处问题了，歧义问题，大家请教教我，，谢谢
}
::copy_if
