//法一  使用sizeof
int main(int argc, char *argv[])
{
    
    int arr[] {2,6,3,1,9,8,10,5,4,0};
    
    int length = sizeof (arr) / sizeof (arr[0]);
    
    std::cout << "array arr's length =" << length<< std::endl;
    
    return 0;
}

//法二   begin(),end()
int main(int argc, char *argv[])
{
    
    int arr[] {2,6,3,1,9,8,10,5,4,0};
    
    //计算数组长度
    int length = std::end(arr) - std::begin(arr);
    std::cout << "array arr's length =" << length<< std::endl;
    
    return 0;
}