analog pin like digital pin

Using Arduino Programming Questions
1

I am using the arduino ethernet and I want to know if I can use whatever analog pin like digital output pin

which could be the code?

2

Yes you can.
A0 to A5 are D14 to D19.

3

On the Arduino UNO (and earlier) boards using the ATmega168/328 the analog input pins 0 through 5 can be referenced as digital pins 14 through 19.

Warning: On other boards the analog pins map to other digital pin numbers. It's best to use A0, A1, A2, etc. so that your code will work on other boards.

pinMode(A0, OUTPUT);
pinMode(A3, INPUT_PULLUP);

digitalWrite(A0, digitalRead(A3));

Warning: Some boards have A6 and A7 pins which cannot be used as digital pins.

4

you do not need any special code or just programing like :

int led = 14;

void setup()
{
pinMode(led,OUTPUT);
}

void loop()
{
digitalWrite(led,HIGH);
delay(1000);
digitalWrite(led,LOW);
delay(1000);
}

this code is correct?

5

Correct.

The name "led" might be a special keyword, change it if the IDE shows it as a funny color.
like led14 or something simple.

6

As already pointed out, but important to repeat: Instead of 14, use "A0".

That way when you read the code, you know exactly which pins on the board you mean.