大概是new操作符调用malloc函数分配内存，看不懂

void* __CRTDECL operator new(size_t const size)
{
for (;;)
{
if (void* const block = malloc(size))
{
return block;
}

    if (_callnewh(size) == 0)
    {
        if (size == SIZE_MAX)
        {
            __scrt_throw_std_bad_array_new_length();
        }
        else
        {
            __scrt_throw_std_bad_alloc();
        }
    }

    // The new handler was successful; try to allocate again...
}

}

哪里看不懂？new就是把malloc封装了一下
如果malloc失败，那么抛出一些异常