Please help me to have the source code to implement N-ary Tree in C++

Let's kickstart you solution.

struct node
{
    struct node* parent;
    int number_of_sons;
    struct node* sons;
    int data_int;
    // char[64] data_str;
    // void* data_ptr;
}

Now, you have to implement:

int insert_tree(int data)
{
}

and

struct node* search_tree(int data)
{
}

We do not do your homework: it is set for a reason. It is there so that you think about what you have been told, and try to understand it. It is also there so that your tutor can identify areas where you are weak, and focus more attention on remedial action.

Try it yourself, you may find it is not as difficult as you think!

#include <map>

class tree_1
{
public:
tree_1()
{
data = NULL;
}
protected:
std::map<size_t,tree_1*> next_level_map;
void *data;
};
</map>