用c++语言编写一个函数模板findmin(...)，使该函数能寻找数组中最小元素，将该元素的下标通过参数返回，函数返回值为其地址值，考虑整型、小数等不同类型的数组

好的，下面是我为您编写的代码：

template<typename T>
T* findmin(T* arr, int size, int& index)
{
    if(size <= 0) return nullptr;
    
    index = 0;
    T* min = &arr[0];
    for(int i = 1; i < size; ++i)
    {
        if(arr[i] < *min)
        {
            min = &arr[i];
            index = i;
        }
    }
    return min;
}

这个函数模板可以寻找任意类型的数组中最小元素，并将其下标通过引用参数返回。函数返回值为最小元素的地址。

使用示例：

int main()
{
    int int_arr[] = {5, 2, 9, 1, 7};
    int int_index;
    int* int_min_ptr = findmin(int_arr, 5, int_index);
    cout << "The minimum value is " << *int_min_ptr << ", and its index is " << int_index << endl;
    
    double double_arr[] = {3.14, 1.23, 2.71, 0.99};
    int double_index;
    double* double_min_ptr = findmin(double_arr, 4, double_index);
    cout << "The minimum value is " << *double_min_ptr << ", and its index is " << double_index << endl;
    
    return 0;
}

输出结果：

The minimum value is 1, and its index is 3
The minimum value is 0.99, and its index is 3