char char_array_value[8];
char* txt;
char *msg;
char char_array_number[8];
char char_array_number_temp1[8];
char char_array_number_temp2[8];
int int_number;
int int_number_2;
char char_path[30];
char char_MacAddressWiFi[18];


void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Programm Start");
  //------------------------------------------------------
  //1st approach to load value to string using C string.h functions:
  strcpy(char_array_value,"cheers");
  Serial.println(char_array_value);
  //------------------------------------------------------
  //2nd approach to load value to string using C string.h functions:
  sprintf(char_array_value,"hello");
  Serial.println(char_array_value); 
  //------------------------------------------------------
  txt = "bye";  
  Serial.println(txt);
  //------------------------------------------------------
  msg = "thanks";  
  Serial.println(msg);
  //------------------------------------------------------
  sprintf(char_array_number,"1234");
  Serial.println(char_array_number); 
  //------------------------------------------------------
  int_number = atoi(char_array_number);
  Serial.println(int_number);
  //------------------------------------------------------
  int_number_2 = 5;
  
  itoa(int_number_2,char_array_number_temp1,10);
  Serial.print("char_array_number_temp1: ");
  Serial.println(char_array_number_temp1);

  strcpy(char_array_number_temp2,"0");
  strcat(char_array_number_temp2, char_array_number_temp1);

  Serial.print("char_array_number_temp2: ");
  Serial.println(char_array_number_temp2);
  //------------------------------------------------------
}

void loop() {
  //------------------------------------------------------
  // this approach works:
  if(int_number == 1234)
  {
    Serial.println("yes");
  }
  else{
    Serial.println("no");
  }


  //------------------------------------------------------
  // this approach works:
  if(txt == "bye")
  {
    Serial.println("yes");
  }
  else{
    Serial.println("no");
  }
  //------------------------------------------------------
  // DO NOT USE, this approach doesn´t works:
  if(char_array_value == "hello")
  {
    Serial.println("yes");
  }
  else{
    Serial.println("no");
  }
  //------------------------------------------------------
  // this approach works:
  if(strcmp(char_array_value,"hello") == 0) //0 indicates str1 is equal to str2.
  {//equal:
    Serial.println("yes");
  }
  else
  {//different:
    Serial.println("no");
  }
  //------------------------------------------------------

  //------------------------------------------------------
  Serial.println("Programm Stop");
  while(1);
}

void firebaseSetCharArray(char* path, char* var, char* value) 
{
//  String Path = path + MacAddressWiFi + "/" + var;
//  String Value = value;

  strcpy(char_path,path);
  strcat(char_path,char_MacAddressWiFi);
  strcat(char_path,"/");
  strcat(char_path,var);
}