新手菜鸟遇到问题， 希望高手解决下

#include <iostream>
#include <cstring>

struct node
{
    char f_name[20];
};
int main()
{
    using namespace std;
    node* p = new node;
    p->f_name = "mary";
    char* name = new char[20];
    cin >> name;
    cout << name << endl;
    strcpy_s(name, 4, p->f_name);
    cout << name << endl;
    delete name;
    return 0;
}


问题是: p->f_name = "mary";     error C2440: “=”: 无法从“const char [5]”转换为“char [20]”