简单UDP套接字代码，发送和接收消息

我只是学习UDP套接字，这是我的第一个涉及它的代码。我有两个来回发送和接收信息的程序。我的问题是，似乎我必须声明我在整个代码中多次发送/接收哪个IP地址，因为它发生了变化，但我觉得有一种更好的方法可以做到这一点，而无需在代码中手动更改inet_addr。从我的阅读来看，sendto和recvfrom可能会有所帮助，但我不确定如何在这种情况下使用它们。如果有人能告诉我如何解决我的简单问题，我会非常感激!由于

CODE 1: Send then Receive

int main(int argc, char *argv[])
{
//initialize socket and structure
int socket_info;
struct sockaddr_in server;
char message[100];
char incoming_message[100];
printf("Input Message: ");
fgets(message, 100, stdin);
    //create socket
    socket_info = socket(AF_INET, SOCK_DGRAM, 0);
    if (socket_info == -1) {
    printf("Could not create socket");
    }
//assign local values
    server.sin_addr.s_addr = inet_addr("172.21.8.178");
    server.sin_family = AF_INET;
    server.sin_port = htons( 1100 );
    //binds connection
    if (bind(socket_info, (struct sockaddr *)&server, sizeof(server)) < 0) {    
perror("Connection error");
       return 1;
    }
    puts("Bind");
    //assign new value to connect to
    server.sin_addr.s_addr = inet_addr("172.21.8.179");
    //checks connection 
    if (connect(socket_info, (struct sockaddr *)&server, sizeof(server)) <       0) {
    perror("Connection error");
       return 1;
    }
    puts("Connected");
    //sends message
if(send(socket_info, message, strlen(message), 0) <0) {        
perror("Send failed");
    return 1;
    }
    puts("Message Sent");
//receives message back    
if(recv(socket_info, incoming_message, sizeof(incoming_message), 0) <0) {    
puts("Received failed");
    return 1;
    }
    puts("Message received");
    puts(incoming_message);
close(socket_info);
}

CODE 2: Receive then Send

int main(int argc, char *argv[])
{
//initialize socket and structure
int socket_info;
struct sockaddr_in server;
char incoming_message[100];
    //create socket
    socket_info = socket(AF_INET, SOCK_DGRAM, 0);
    if (socket_info == -1) {
    printf("Could not create socket");
    }
    //assign values
    server.sin_addr.s_addr = inet_addr("172.21.8.179");
    server.sin_family = AF_INET;
    server.sin_port = htons( 1100 );
    //checks connection
    if (bind(socket_info, (struct sockaddr *)&server, sizeof(server)) < 0) {
    perror("Connection error");
       return 1;
    }
    puts("Bind");
    //Receive an incoming message
if( recv(socket_info, incoming_message, sizeof(incoming_message), 0) < 0) {      
puts("Received failed");
    return 1;
    }
    puts("Message received");
    puts(incoming_message);
server.sin_addr.s_addr = inet_addr("172.21.8.178");
if (connect(socket_info, (struct sockaddr *)&server, sizeof(server)) < 0) {
    perror("Connection error");
     return 1;
    }
    puts("Connected");
//Sends message back
char message[100];
printf("Input Message: ");
fgets(message, 100, stdin);
if(send(socket_info, message, strlen(message), 0) <0) {        
perror("Send failed");
    return 1;
    }
    puts("Message Sent");
close(socket_info);
}