Combining code for multiple sensors in one program I need to operate 2 different sensors (gas and temp) simultaneously. 
I have managed to run each one of them separately and I don't know how to manipulate the code so they could work together. My background in coding is basic and I'm not the one who wrote these codes.

Here are the sketches:

Thermistor code:

void setup() {
  //This function gets called when the Arduino starts
  Serial.begin(9600);
  //This code sets up the Serial port at 9600 baud rate
}

void loop() {
  //This function loops while the arduino is powered
  int val; //Create an integer variable
  val=analogRead(0);
  //Read the analog port 0 and store the value in val
  Serial.println(val);
  //Print the value to the serial port
  delay(1000);
  //Wait one second before we do it again
}


This is the gas detector code:

/* GAS Sensor MQ-2
This sensor detects flammable gasses
the board has four pins
connect AO to Arduino pin A0
connect DO to Arduino pin 2
connect Gnd to Arduino Gnd
connect Vcc to Arduino 5 volts
*/

int sensorPin = A0;
// select the input pin for the potentiometer
int DOPin = 2;
// select the pin for the LED
int sensorValue = 0;
// variable to store the value coming from the sensor
int ledPin =13;

void setup() {
  // declare the ledPin as an OUTPUT:
  pinMode(DOPin, INPUT);
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  // read the value from the sensor:
  sensorValue = analogRead(sensorPin);
  Serial.print("Analog Output = ");
  Serial.println(sensorValue);
  // turn the ledPin on if triggered
  if (digitalRead(DOPin) ==HIGH) {
    digitalWrite(ledPin, LOW);
    Serial.println("Digital Output = OFF");
  } else {
    digitalWrite(ledPin, HIGH);
    Serial.println("Digital Output = ON");
  }
  delay(1000);
}
You just need to assign the sensors different pins.

/* GAS Sensor MQ-2
This sensor detects flammable gasses
the board has four pins
connect AO to Arduino pin A0
connect DO to Arduino pin 2
connect Gnd to Arduino Gnd
connect Vcc to Arduino 5 volts
*/

int gasSensorPin= A0; // GAS sensor pin
int DOpin= 2; // select the pin for the LED
int gasSensorValue= 0; // variable to store the value coming from the sensor
int ledPin = 13;

int tempSensorPin = A1;  //Temperature sensor pin
int tempSensorValue;

void setup() {
 // declare the ledPin as an OUTPUT:
 pinMode(DOPin, INPUT);
 pinMode(ledPin, OUTPUT);
 Serial.begin(9600);
 }


void loop() {
 // read the value from the sensor:
 gasSensorValue= analogRead(gasSensorPin);
 Serial.print("Analog Output = ");
 Serial.println(gasSensorValue);
 // turn the ledPin on if triggered
 //
 if (digitalRead(DOpin) == HIGH){
 digitalWrite(ledPin, LOW);
 Serial.println("Digital Output = OFF");
 }
   else {
     digitalWrite(ledPin, HIGH);
     Serial.println("Digital Output = ON");
  }

Serial.print("Temperture: ");
tempSensorValue = analogRead(tempSensorPin));
Serial.println(tempSensorPin);  //Print the value of pin A4

delay(1000);
}


This is your combined sketch.