聊聊c++數組名稱和sizeof的問題

int main() {

    //數組名用途
    //1、可以獲取整個數組占用內存空間大小
    int arr[10] = { 1,2,3,4,5,6,7,8,9,10 };
    cout << "整個數組所占內存空間為： " << sizeof(arr) << endl;
    cout << "每個元素所占內存空間為： " << sizeof(arr[0]) << endl;
    cout << "數組的元素個數為： " << sizeof(arr) / sizeof(arr[0]) << endl;
    //2、可以通過數組名獲取到數組首地址
    cout << "數組首地址為： " << (int)arr << endl;
    cout << "數組中第一個元素地址為： " << (int)&arr[0] << endl;
    cout << "數組中第二個元素地址為： " << (int)&arr[1] << endl;
    //arr = 100; 錯誤，數組名是常量，因此不可以賦值
    system("pause");
    return 0;
}

int main() {

    //二維數組數組名
    int arr[2][3] =
    {
        {1,2,3},
        {4,5,6}
    };
    cout << "二維數組大小： " << sizeof(arr) << endl;
    cout << "二維數組一行大小： " << sizeof(arr[0]) << endl;
    cout << "二維數組元素大小： " << sizeof(arr[0][0]) << endl;
    cout << "二維數組行數： " << sizeof(arr) / sizeof(arr[0]) << endl;
    cout << "二維數組列數： " << sizeof(arr[0]) / sizeof(arr[0][0]) << endl;
    //地址
    cout << "二維數組首地址：" << arr << endl;
    cout << "二維數組第一行地址：" << arr[0] << endl;
    cout << "二維數組第二行地址：" << arr[1] << endl;
    cout << "二維數組第一個元素地址：" << &arr[0][0] << endl;
    cout << "二維數組第二個元素地址：" << &arr[0][1] << endl;
    system("pause");
    return 0;
}

#include <iostream>
using namespace std;

template<class T>
int length(T& data)
{undefined
    return sizeof(data)/sizeof(data[0]);
}
int main（）{undefined
int data[]={2,45,7,8,9,23,4,6,7,8,0};
 int data1[12];
 int *data2 = new int[13];
 char *data3 = new char[10];
 cout<<length(data)<<" "<<sizeof(data[0])<<" "<<sizeof(data)<<endl;
 cout<<length(data1)<<" "<<sizeof(data1[0])<<" "<<sizeof(data1)<<endl;
 cout<<length(data2)<<" "<<sizeof(data2[0])<<" "<<sizeof(data2)<<endl;
 cout<<length(data3)<<" "<<sizeof(data3[0])<<" "<<sizeof(data3)<<endl;
 return 0;