Error message on an if statement

Projects Programming
1

Hello everyone,
I'm trying to build a program which turns off and on an LED based on what the PubNub user sends. The PubNub message is denoted as "c" and is a pointer. I'm getting the following error message:

ISO C++ forbids comparison between pointer and integer [-fpermissive]

on lines:
if (c == "ON")

if(c == "OFF")

I've also tried using constant strings such as 'on' but that gave me this error:

character constant too long for its type

Please let me know if you have any ideas to fix this. All responses are greatly appreciated. Thank you.

subscribemessageled.ino (1.48 KB)

2

You say:
if (c == "ON")
if(c == "OFF")

You have:
if (c == ‘ON’) “ is not the same as ‘
if(c == ‘OFF’)

3 
   char c = pclient->read();

But c is only a single character anyway so will never equal "ON", "OFF", 'ON' or 'OFF'

4

The code.
In code tags.

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

byte mac [] = {0XDE,0XAD,0XBE,0XEF,0XFE,0XED};
char pubkey[] = "demo";
char subkey[] = "demo";
char channel[] = "iotchannel";
int ledPin = 9;

void setup() {
  Serial.begin(9600);
  Serial.println("Serial set up");
  while(!Ethernet.begin(mac))
  { 
    Serial.println("Ethernet setup error");
    delay(1000);
  }
  PubNub.begin(pubkey,subkey);
  Serial.println("PubNub set up");

  pinMode(ledPin, OUTPUT);

}

void loop() {
  Ethernet.maintain();
  EthernetClient*client;
  Serial.println("publishing message");
  client = PubNub.publish(channel, "\"enter ON to turn on LED or OFF to turn off LED\"");
  if(!client){
    Serial.println("PubNub Error");
    delay(1000);
    return;
  }
    while(client->connected()&&client->available())
    {
    char c = client->read();
    Serial.print(c);
  }
  /*stop disconnects it from the server*/
  client->stop();
  Serial.println();
  Serial.println("Waiting for subscribe message");
  //subscribe function
  PubSubClient *pclient = PubNub.subscribe(channel);
  if(!pclient){
    Serial.println("Sub fail");
    delay(1000);
    return;
  }
  
  while(pclient->wait_for_data())
  {
   char c = pclient->read();
   //turn on led if the subscribe message is ON
    if (c == 'ON')
    {
     digitalWrite(ledPin, HIGH); 
    }
    //turn off led if the subscribe message is OFF
    if (c == 'OFF')
    {
      digitalWrite (ledPin, LOW);
    } 
    //Serial.print(c);
  }
  pclient->stop();
  Serial.println();
}
5

UKHeliBob:

   char c = pclient->read();

But c is only a single character anyway so will never equal "ON", "OFF", 'ON' or 'OFF'

Thanks. I fixed it by changing c into a string

6

I fixed it by changing c into a string

Perhaps you could post your revised code for the benefit of anyone reading this thread in the future