Failed to listen to or bind port 80 in Linux

I wrote a program and tried to listen on port 80. As a result, the execution of the bind failed.
The program is as follows:

 

Sockaddr_in sock_addr;
Memset (& sock_addr, 0, sizeof (sock_addr ));
Sock_addr.sin_family = AF_INET;
Sock_addr.sin_addr.s_addr = host_inet_addr;
Sock_addr.sin_port = htons (m_local_port); // m_local_port = 80
Ret = bind (m_socket_fd, (const sockaddr *) & sock_addr, sizeof (sockaddr_in ));

Ret is-1.
Then, change m_local_port to 8080. Suddenly, the system does not allow user programs to listen on Ports 1-because they are well-known ports.
So how can I listen on a well-known port? Obviously, there are no programs running on port 80 on my machine, so there must be a way, not at my program level.
Therefore, if su is used and replaced with the root user, the bind is successful.

Record it.