Unexpected code error

[andrewcuse1]

Hi, I was just writing some code and an unexpected error occurred here:

#include <LiquidCrystal.h>

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
#include "DHT.h"

#define DHTPIN 2     // what pin we're connected to

// Uncomment whatever type you're using!
#define DHTTYPE DHT11   // DHT 11 


DHT dht(DHTPIN, DHTTYPE);
int humi = 0;
int input = 15;
int output = 14;
void setup() {
    lcd.begin(16, 2);
    dht.begin();
    lcd.noDisplay();
    delay(100);
    lcd.display();
    lcd.write("Greenhouse system");
    delay(3000);
    lcd.clear();
    delay(30);
    lcd.write("Loading info ...");
    delay(3000);
    lcd.clear();
    delay(100);
}

void loop(){
  delay(2000);
     float h = dht.readHumidity();
  // Read temperature as Celsius
  float t = dht.readTemperature();
  // Read temperature as Fahrenheit
  float f = dht.readTemperature(true);
   lcd.setCursor(1, 1);
   lcd.write("Temp(f)= ");
   lcd.setCursor(10, 1);
   lcd.write(dht.readTemperature());
   lcd.setCursor(1, 2);
   lcd.write("Humidity = ");
   lcd.setCursor(12, 2);
   lcd.write(dht.readHumidity());
   humi = analogRead(input);
   output = analogWrite(humi);
}

Then the compiler says this:

/tmp/802097090/sketch_jul24a/sketch_jul24a.ino: In function 'void loop()':

/tmp/802097090/sketch_jul24a/sketch_jul24a.ino:51:29: error: too few arguments to function 'void analogWrite(uint8_t, int)'

output = analogWrite(humi);

^

In file included from /tmp/802097090/build/sketch/sketch_jul24a.ino.cpp:1:0:

/home/builder/.arduino15/packages/arduino/hardware/avr/1.8.3/cores/arduino/Arduino.h:139:6: note: declared here

void analogWrite(uint8_t pin, int val);

^~~~~~~~~~~

exit status 1

[anon73444976]

What's unexpected about an error concerning assigning a value that a function doesn't return?

[DrAzzy]

It means exactly what it says - too few arguments. analogWrite() takes 2 arguments - a pin, a number between 0 and 255 representing the desired duty cycle?

Also, you're setting a variable equal to the value returned by analogWrite(). Which returns nothing

[UKHeliBob]

output = analogWrite(humi);

analogWrite takes 2 arguments, pin number and value and does not return a value. Did you perhaps mean to use analogRead() ?

[andrewcuse1]

Its weird because this error has not happened before.

[UKHeliBob]

Maybe you have never made that mistake before

[cattledog]

#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
#include "DHT.h"
#define DHTPIN 2     // what pin we're connected to

Pin 2 should not be connected to both the lcd and the dht sensor.

[jremington]

I learned long ago to expect "unexpected errors" when I write code.

I also learned that the compiler and linker error messages usually give helpful hints about how to solve those unexpected problems.