Help understanding the code : (char)payload[i];

Using Arduino Programming Questions
#1

Hi there,

I’m working on this tutorial MQTT Tutorial for Raspberry Pi, Arduino, and ESP8266 - Bald Engineer

I’m confused with the byte* payload in the callback function becoming (char)payload*;*
Is the (char) before payload*; is a kind to convert data from payload parameter to char?*
Any help would be appreciated.
Here the code:
*_ <em>*void callback(char* topic, byte* payload, unsigned int length) { Serial.print("Message arrived ["); Serial.print(topic); Serial.print("] "); for (int i=0;i<length;i++) {   char receivedChar = (char)payload[i];   Serial.print(receivedChar);   if (receivedChar == '0')   // ESP8266 Huzzah outputs are "reversed"   digitalWrite(ledPin, HIGH);   if (receivedChar == '1')   digitalWrite(ledPin, LOW);   }   Serial.println(); }*</em> _*
Moderator edit: I’m fed up of asking people to use CODE TAGS.

#2

You are converting from one type (byte) to another (char). On most arduino boards, a byte is an 8-bit unsigned value and a char is an 8-bit signed value. I’m not sure about an eSP8266…

#3

blh64:
You are converting from one type (byte) to another (char). On most arduino boards, a byte is an 8-bit unsigned value and a char is an 80-bit signed value. I'm not sure about an eSP8266...

That's "8 bit signed value"

#4