fatal error: WProgram.h: No such file or directory,

C:\Users\Lenovo\Documents\Arduino\libraries\SHT1x/SHT1x.h:15:22: fatal error: WProgram.h: No such file or directory

compilation terminated.

Using library SHT1x in folder: C:\Users\Lenovo\Documents\Arduino\libraries\SHT1x (legacy)
exit status 1
Error compiling for board Arduino/Genuino Uno.

#include <SHT1x.h>

// Specify data and clock connections and instantiate SHT1x object
#define dataPin 10
#define clockPin 11
SHT1x sht1x(dataPin, clockPin);

void setup()
{
Serial.begin(38400); // Open serial connection to report values to host
Serial.println(“Starting up”);
}

void loop()
{
float temp_c;
float temp_f;
float humidity;

// Read values from the sensor
temp_c = sht1x.readTemperatureC();
temp_f = sht1x.readTemperatureF();
humidity = sht1x.readHumidity();

// Print the values to the serial port
Serial.print("Temperature: ");
Serial.print(temp_c, DEC);
Serial.print("C / ");
Serial.print(temp_f, DEC);
Serial.print(“F. Humidity: “);
Serial.print(humidity);
Serial.println(”%”);

delay(2000);
}

ReadSHT1xValues.pde (957 Bytes)

Open C:\Users\Lenovo\Documents\Arduino\libraries\SHT1x/SHT1x.h in a text editor.

Change line 15 from:

#include <WProgram.h>

to:

#include <Arduino.h>

Save the file.

Note that this error indicates the SHT1x library is very old and unmaintained. You might want to look around to see if a newer version of the library is available.