def register(connection):
    data = connection.recv(BUFSIZE)
    username = data.decode("utf-8")

    case_register = checkUsername(username)

    while case_register == 0:
        msg="Username has already been registered\nEnter Username again"
        connection.send(bytes(msg, "utf-8"))
        data =connection.recv(BUFSIZE)
        username = data.decode("utf-8")
        case_register=checkUsername(username)
    
    msg="Valid Username!"
    connection.send(bytes(msg, "utf-8"))



    data = connection.recv(BUFSIZE)
    password = data.decode("utf-8")
    print(f"{username}")
    print(f"{password}")
    msg = "Register Successfully"
    connection.send(bytes(msg, "utf-8"))

    f = open('DataLogin.txt','r+')
    lst=[]
    num_clients = f.readline()
    num_clients=int(num_clients)
    lst.append(num_clients)
    for i in range(1, num_clients+1):
        login_user = f.readline()
        login_user=login_user.strip()
        lst.append(login_user)
        login_pass = f.readline()
        login_pass=login_pass.strip()
        lst.append(login_pass)
    f.close()

    lst.append(username)
    lst.append(password)
    fin=open('DataLogin.txt','w+')
    lst[0]=lst[0]+1
    fin.write(str(lst[0]))
    fin.write("\n")

    for i in range(1,len(lst)+1):
        fin.write(lst[i])
        fin.write("\n")
    fin.close()