Ask a few simple questions. How do you understand this?

Ask a few simple questions. How do you understand this? -- Linux general technology-Linux programming and kernel information. The following is a detailed description. Connection-oriented communication in unix domain.
Question 1: I have defined static char buffer [1024]. Why do I need to use the memset function to open up space when using the strcpy function to assign values to the buffer:
Memset (buffer );
Strcpy (buffer, "send from server ");

Question 2: struct sockaddr
(
Unsigned short sa_family;
Char sa_data [14];
)

Struct sockaddr_un
{
Sa_family_t sun_family;
Char sun_path [UNIX_PATH_MAX];
}

Struct sockaddr_un srv_addr;
Ret = bind (listen_fd, (struct sockadd *) & srv_addr, sizeof (srv_addr ));


Can this happen? (Struct sockadd *) & srv_addr