16-relay code - updated.

#include <SPI.h>
#include <Ethernet.h>
#include <PubSubClient.h>

#define datapin 2
#define clockpin 3
#define latchpin 4
int current = 0;        // 00000000
const int relayValues[]={
  1,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768};
int relayCheck[] = {
  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
int changeVal = 0;
//char OnOrOff[] = {"off","on"};
//char DataResult[100]="Publishing data - relay "; //24
String OnOrOff;
String DataMash;
String DataResult;
byte mac[] = {
  0xDE, 0xC0, 0xDE, 0xC0, 0xFF, 0xEE };
byte mqttserver[] = {
  192, 168, 2, 7 };
byte ip[] = {
  192, 168, 2, 101 };

//char DataMash[30]="                             ";

EthernetClient ethClient;
PubSubClient clientr(mqttserver, 1883, callback);

/////////////////// calculateRelayVal ///////////////////
int calculateRelayVal(int newVal) {

  // if newVal==0 then return value as 11111111
  // newVal has relay we need to toggle
  // referenced in relayCheck as newVal-1
  int intRelayToWorkWith = relayValues[(newVal-1)];

  if(relayCheck[(newVal-1)]==0) {
    // relay is currently off, turn on
    changeVal = current | intRelayToWorkWith;
    relayCheck[(newVal-1)]=1;
  }
  else {
    // relay is currently on, turn off
    changeVal = current ^ intRelayToWorkWith;
    relayCheck[(newVal-1)]=0;
  }

  current = changeVal;
  return current;
}

/////////////////// doWork ///////////////////
void doWork(int val) {

  // as relays need a '0' to turn on and a '1' to turn off, need to NOT this value
  unsigned int realVal = ~val;

  uint8_t rVlow = realVal & 0xff;
  uint8_t rVhigh = (realVal >> 8);

  digitalWrite(latchpin,LOW);
  shiftOut(datapin,clockpin,MSBFIRST,rVhigh);
  shiftOut(datapin,clockpin,MSBFIRST,rVlow);
  digitalWrite(latchpin,HIGH);

}

/////////////////// callback ///////////////////
static void callback(char* topic, byte* payload, unsigned int length) {
  char PublishData[24];
  char tina[4];
  String tp = (char*)payload;
  (tp.substring(0,length)).toCharArray(tina,4);
  unsigned int readVar = (unsigned int)atoi(tina);

  if(readVar<0 || (readVar>16 && readVar!=999)) {
    // if input is outside of specification (greater than 16 and not 999 (status check) or less than zero then make -1
    // -1 is used in the switch below to indicate invalid input
    readVar=-1;
  }
  if(readVar==999){
    String strGetStatus="S:";
    for(int i=0;i<16;i++){
      strGetStatus+=relayCheck[i];
    }
    strGetStatus.toCharArray(PublishData,100);
    //    clientr.publish("RelayControlReport",PublishData);
    clientr.publish("WebControl",PublishData);
  }
  else {
    if(readVar>=0 && readVar<=16) {
      int registerValue=0;
      if(readVar > 0) {
        registerValue = calculateRelayVal(readVar);
      }
      else {
        current=0;
        for(int i=0;i<16;i++){
          relayCheck[i]=0;
        }
      }
      doWork(registerValue);

      if(relayCheck[(readVar-1)]==1){
        OnOrOff=" on";
      }
      else {
        OnOrOff=" off";
      }

      if(readVar!=0){
        DataMash="Relay: ";
        DataResult = DataMash + readVar + OnOrOff;
        DataResult.toCharArray(PublishData,100);
      }
      else {
        DataResult="All relays off";
        DataResult.toCharArray(PublishData,100);
      }
      clientr.publish("RelayControlReport",PublishData);
    }
  }
}

/////////////////// setup ///////////////////
void setup()
{
  pinMode(datapin,OUTPUT);
  pinMode(clockpin,OUTPUT);
  pinMode(latchpin,OUTPUT);

  digitalWrite(latchpin,LOW);
  shiftOut(datapin,clockpin,MSBFIRST,-1);
  shiftOut(datapin,clockpin,MSBFIRST,-1);
  digitalWrite(latchpin,HIGH);

  delay(500);
  Serial.begin(9600);
  Serial.println(F("Scouris - MQTT Control, booting up."));
  Serial.print(F("Eth start .."));
  Ethernet.begin(mac,ip);

  // below is for when running with DHCP
  Serial.print(F("up, IP: "));
  for (byte thisByte = 0; thisByte < 4; thisByte++) {
    // print the value of each byte of the IP address:
    Serial.print(Ethernet.localIP()[thisByte], DEC);
    Serial.print(F("."));
  }
  Serial.println("");

  if(clientr.connect("arduinoClient")) {
    clientr.publish("checkInTopic","Relay Controller Online");
    clientr.publish("RelayControlReport","Relay Controller Online");
    clientr.subscribe("RelayControl");
  }
  doWork(0);
  //  delay(500);
}

/////////////////// loop ///////////////////
void loop()
{
  clientr.loop();
}