Ошибка компиляции: template-id does not match any template declaration

#include <iostream>
using namespace std;
 
template <typename T>
T maxn(T*, const int*);
 
template <>
char* maxn<char*>(char*, const int*);
 
int main(int argc, char **argv)
{
    //test arrays:
    const int ari_size = 6;
    int ari[ari_size] = {7, 11, 7, 9, 9, 21};
    const int ard_size = 4;
    double ard[ard_size] = {4.1, 0.01, 71.9, 43};
    const int ars_size = 5;
    const char* ars[ars_size] = {
        "Jammy house",
        "Extraterrestial intelligence",
        "Generally electrical",
        "Free Kenny",
        "Central substance"
    };
    
    return 0;
}
 
template <typename T>
T maxn(const T* ar, const int* limit) {
    T curmax = 0, absmax = 0;
    for (int i = 1; i < *limit; ++i)
        if (ar[i] > ar[i-1]) {
            curmax = ar[i];
            if (curmax > absmax)
                absmax = curmax;
        }
    return absmax;
}
 
template <>
char* maxn<char*>(char* ar, const int* limit) {
    int curmax = 0, absmax = 0, max_ind = 0;
    for (int i = 0; i < *limit; ++i) {
        while (ar[i][j] != '\0')
            ++j;
        if (j > curmax) {
            curmax = j;
            if (curmax > absmax) {
                absmax = j;
                max_ind = i;
            }
        }
    }
    return ar[max_ind];     
}

template <typename T>
T maxn(const T* ar, const int* limit)
/* .... */
template <>
char* maxn<char*>(char* ar, const int* limit)
/* ... */

template <>
char maxn<char>(const char* ar, const int* limit)

template <>
char* maxn<char*>(const char** ar, const int* limit)

template<typename T>
T func(T t)

template<>
char func<char>(char* t)
 
template<>
int func<int>(string t)

template <> char** maxn<char**>(char **ar, int n)
{
...
    return &ar[index_of_max_length_string];
}