data = client.recv(BUFSIZE)
    username = data.decode("utf-8")

    case_register=checkRegister(client)

    while case_register==0:
        msg="Username has already been registered\nEnter Username again"
        client.send(bytes(msg, "utf-8"))
        data = client.recv(BUFSIZE)
        username = data.decode("utf-8")
        case_register=checkRegister()
    
    data = client.recv(BUFSIZE)
    password = data.decode("utf-8")
    msg="Register Successfully"
    client.send(bytes(msg, "utf-8"))

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

    f=open('DataLogin.txt','w')
    num_clients=num_clients+1
    num_clients=f.write()
    for i in range(a,num_clients):
        lst[i]=f.write()
    username=f.write()
    password=f.write()
    f.close()