服务器端代码（server.cj）

// 服务器端
import "udp"

func main() {
    var serverAddr = "0.0.0.0" // 服务器监听所有网卡
    var serverPort = 12345     // 服务器监听端口

    // 创建UDP Socket
    var serverSocket = udp.createSocket()
    if serverSocket < 0 {
        println("Error creating server socket")
        return
    }

    // 绑定服务器地址和端口
    var bindResult = udp.bind(serverSocket, serverAddr, serverPort)
    if bindResult < 0 {
        println("Error binding server socket")
        udp.closeSocket(serverSocket)
        return
    }

    println("UDP server listening on ", serverAddr, ":", serverPort)

    // 接收客户端发送的数据
    var buffer[1024]
    var clientAddr
    var clientPort

    loop {
        var bytesReceived = udp.recvFrom(serverSocket, buffer, clientAddr, clientPort)
        if bytesReceived < 0 {
            println("Error receiving data")
            break
        }

        var receivedData = buffer[0:bytesReceived]
        println("Received from ", clientAddr, ":", clientPort, " - ", receivedData)

        // 回复客户端
        var bytesSent = udp.sendTo(serverSocket, receivedData, clientAddr, clientPort)
        if bytesSent < 0 {
            println("Error sending data back to client")
        }
    }

    // 关闭服务器端Socket
    udp.closeSocket(serverSocket)
}
客户端代码（client.cj）

// 客户端
import "udp"

func main() {
    var serverAddr = "127.0.0.1" // 服务器IP地址
    var serverPort = 12345       // 服务器端口

    // 创建UDP Socket
    var clientSocket = udp.createSocket()
    if clientSocket < 0 {
        println("Error creating client socket")
        return
    }

    // 准备发送的数据
    var sendData = "Hello UDP Server!"
    var sendBytes = udp.sendTo(clientSocket, sendData, serverAddr, serverPort)
    if sendBytes < 0 {
        println("Error sending data")
        udp.closeSocket(clientSocket)
        return
    }

    println("Data sent to server: ", sendData)

    // 接收服务器返回的数据
    var buffer[1024]
    var serverAddrReceived
    var serverPortReceived
    var recvBytes = udp.recvFrom(clientSocket, buffer, serverAddrReceived, serverPortReceived)
    if recvBytes < 0 {
        println("Error receiving data from server")
    } else {
        var receivedData = buffer[0:recvBytes]
        println("Received from server: ", receivedData)
    }

    // 关闭客户端Socket
    udp.closeSocket(clientSocket)
}