What is the difference between TCP and UDP protocols?

TCP is connection-oriented, guarantees delivery and packet order. UDP is connectionless, does not guarantee delivery or order, but is faster.

Main differences:

Feature	TCP	UDP
Orientation	With connection establishment	Without connection establishment
Reliability	High (guarantees delivery)	Low (does not guarantee delivery)
Order	Guaranteed	Not guaranteed
Flow control	Present	Not present
Error control	Present (transmission and sequence)	Not present (basic checksum)
Speed	Lower	Higher
Usage	HTTP, FTP, SSH	DNS, DHCP, online games, streaming

Example code for sending data over TCP in Go:

package main

import (
	"net"
	"log"
)

func main() {
	conn, err := net.Dial("tcp", "localhost:8080") // Establish TCP connection
	if err != nil {
		log.Fatal(err)
	}
	defer conn.Close() // Ensure connection closure

	_, err = conn.Write([]byte("Hello, TCP!")) // Send data
	if err != nil {
		log.Fatal(err)
	}
}

Example code for sending data over UDP in Go:

package main

import (
	"net"
	"log"
)

func main() {
	addr, err := net.ResolveUDPAddr("udp", "localhost:8081") // Define UDP address
	if err != nil {
		log.Fatal(err)
	}

	conn, err := net.DialUDP("udp", nil, addr) // Create UDP "connection" (without session establishment)
	if err != nil {
		log.Fatal(err)
	}
	defer conn.Close() // Close socket

	_, err = conn.Write([]byte("Hello, UDP!")) // Send data
	if err != nil {
		log.Fatal(err)
	}
}