关于strcpy_s

#include"stdafx.h"
#include<iostream>
#include<cstring>
int main()
{
    using namespace std;

    char animal[20] = "bear";
    const char* bird = "wren";
    char* ps;

    cout << "Enter a kind of animal: ";
    cin >> animal;
    ps = animal;

    cout << "Before using strcpy_s(): " << endl;
    cout << animal << " at " << (int *)animal << endl;
    cout << ps << " at " << (int*)ps << endl;

    ps = new char[strlen(animal) + 1];
    cout << "sizeof ps: " << sizeof ps << endl;
    strcpy_s(ps,strlen(animal)+1, animal);
    cout << "After using strcpy_s(): " << endl;
    cout << animal << " at " << (int *)animal << endl;
    cout << ps << " at " << (int*)ps << endl;

    delete [] ps;
    cin.get();
    cin.get();
    return 0;
}

strlen 三个参数的情况下，第二个参数表示numberOfElements