ambiguous overload with ostream-CodePudding

I'm stuck with this why trying to overlap ostream of std::array in c . (error: ambiguous overload for 'operator<<' (operand types are 'std::ostream' {aka 'std::basic_ostream'} and 'const char [2]') here is my script:

#include <bits/stdc  .h>

using namespace std;

template<typename T>
ostream& operator <<(ostream& out, T& arr)
{
    bool pre = false;
    for(auto& i : arr)
    {
        if(pre) out << ' ';
        pre = true;
        out << i;
    }
    return out;
}

signed main()
{
    array<int, 4> a = {123, 123, 12, 12};
    cout << a << "\n";
    return 0;
}

CodePudding user response：

This forces the overload to take only std::array, which should solve your ambiguous overload problem:

template<typename T, std::size_t N>
ostream& operator <<(ostream& out, const std::array<T, N> &arr)
{
    bool pre = false;
    for(auto& i : arr)
    {
        if(pre) out << ' ';
        pre = true;
        out << i;
    }
    return out;
}