badly defined output?

I am an absolute beginner with arduino duemilanova.
For exercise i created a sketch to run a steppermotor.
I did it on purpose in a strange way by writing a very simple wave going to an array of 4 outputs.
Using an uln2003a driver, the thing works.
The motor is attached to a potentiometer (5 turns) which returns the position of the motor.
A second identical potentiometer i can change position.
The motor searches now the same position.

int sensorPin1=0;
int sensorPin2=1;
void setup(){
//initialize pins for output
for (int thisPin=2;thisPin<6; thisPin++)
pinMode(thisPin,OUTPUT);
pinMode(sensorPin1,INPUT);
pinMode(sensorPin2,INPUT);

}
void loop (){
int val=analogRead(0);
int var=analogRead(1);
if (val<var-50)//motor forward "to" var
{//forward loop
digitalWrite(2,HIGH);
delay(50);
digitalWrite(2,LOW);
digitalWrite(3,HIGH);
delay(50);
digitalWrite(3,LOW);
digitalWrite(4,HIGH);
delay(50);
digitalWrite(4,LOW);
digitalWrite(5,HIGH);
delay(50);
digitalWrite(5,LOW);
}
if (val>var+50)//reverse going
{digitalWrite(5,HIGH);
delay(50);
digitalWrite(5,LOW);
digitalWrite(4,HIGH);
delay(50);
digitalWrite(4,LOW);
digitalWrite(3,HIGH);
delay(50);
digitalWrite(3,LOW);
digitalWrite(2,HIGH);
delay(50);
digitalWrite(2,LOW);
}
if (val=var)//must stop
{
digitalWrite(2,LOW);
digitalWrite(3,LOW);
digitalWrite(4,LOW);
digitalWrite(5,LOW);
}
}

This stuff works, but not if sensorpins are 1 and 2 instead of 0 and 1.
If i define them as 1 and 2, the !output! number 2 works if nothing is connected(no load at all) 0/5volts.
But if it drives a led or even simply informs the uln2003 input, it gives no more than 1,5volts (off course to little).

Question: Should i do defining in another way, because it should be possible to use inputs with the same id than the outputs.

ps: i know that the idea of running a steppermotor with this kind of sketch is unusual and not prferable, but it is only a way of learning to see if things work out.

Since you are setting pinMode on the pins, it implies that you are referring to digital pins. You never read from the pins, so which pins you reference in the pinMode statements should make no difference.

But, since you never reference the pins again, what is the purpose of setting the mode on them?

if (val=var)//must stop

Psst. This is wrong. = is an assignment operator. The equality operator is ==.

Thanks for explaining the = == mather. and the explaining of the defining of pinMode .
In the meanwhile i had discovered that when i take the definition of the inputs out of my scode, my stuff works.