arduino dht11 library

#include <idDHT11.h>

#include<dht.h>      // Including library for dht
#include<LiquidCrystal.h> 
LiquidCrystal lcd(2, 3, 4, 5, 6, 7);
#define dht11pin 12 
dht11 DHT11;
#define pwm 9
byte degree[8] = 
             {
               0b00011,
               0b00011,
               0b00000,
               0b00000,
               0b00000,
               0b00000,
               0b00000,
               0b00000
             };
void setup()
{
lcd.begin(16, 2);
lcd.createChar(1, degree);
lcd.clear();
lcd.print("   Fan Speed  ");
lcd.setCursor(0,1);
lcd.print("  Controlling ");
delay(2000);
analogWrite(pwm, 255);
lcd.clear();
lcd.print("Circuit Digest ");
delay(2000);
}
void loop()
{
 DHT11.read(dht11pin);
int temp=DHT11.temperature;
 lcd.setCursor(0,0);
 lcd.print("Temperature:");
 lcd.print(temp);   // Printing temperature on LCD
 lcd.write(1);
 lcd.print("C");
 lcd.setCursor(0,1);
 if(temp <26 )
   { 
     analogWrite(9,0);
     lcd.print("Fan OFF            ");
     delay(100);
   }
   
   else if(temp==26)
   {
     analogWrite(pwm, 51);
     lcd.print("Fan Speed: 20%   ");
     delay(100);
   }
   
    else if(temp==27)
   {
     analogWrite(pwm, 102);
     lcd.print("Fan Speed: 40%   ");
     delay(100);
   }
   
    else if(temp==28)
   {
     analogWrite(pwm, 153);
     lcd.print("Fan Speed: 60%   ");
     delay(100);
   }
   
   else if(temp==29)
   {
     analogWrite(pwm, 204);
     lcd.print("Fan Speed: 80%    ");
     delay(100);
   }
    else if(temp>29)
   {
     analogWrite(pwm, 255);
     lcd.print("Fan Speed: 100%   ");
     delay(100);
   } 
 delay(3000);
}

i’m new in Arduino , any one can help me to fix that please.
this is the problem

[ sketch_may14a.ino:3:50: fatal error: dht.h: No such file or directory
compilation terminated.
Multiple libraries were found for “idDHT11.h”

Used: C:\Users\Asus_M\Documents\Arduino\libraries\idDHT11-master

Not used: C:\Program Files (x86)\Arduino\libraries\DHT11

Error compiling.

This report would have more information with
“Show verbose output during compilation”
enabled in File > Preferences.]

Please read How to use the forum and edit your post to include code-tags please.

Next up, why do you have the same library twice?

Arduino IDE does not come with the DHT11 library so you must have placed it here: C:\Program Files (x86)\Arduino\libraries\DHT11. And the Arduino IDE install folder is the wrong place for every library you download. That should always be the libraries folder in your sketchbook (in your case C:\Users\Asus_M\Documents\Arduino\libraries). And the library folder should match the library name, aka remove the "-master" part :wink:

And then the real problem, although you have multiple times the idDHT11 library, you don't have the library dht.h...