Error compiling for board Arduino/Genuino Uno

Here it is:

#include <DHT11.h>

#define dht_apin A0 // Analog Pin sensor is connected to

DHT DHT;

void setup(){

Serial.begin(9600);
delay(500);//Delay to let system boot
Serial.println("DHT11 Humidity & temperature Sensor\n\n");
delay(1000);//Wait before accessing Sensor

}//end "setup()"

void loop(){
//Start of Program
float h = DHT11.readHumidity();

Serial.print("Current humidity = ");
Serial.print(h);
Serial.print("% ");
Serial.print("temperature = ");
Serial.print(t);
Serial.println("C ");

delay(5000);//Wait 5 seconds before accessing sensor again.

//Fastest should be once every two seconds.

}// end loop