Nintendo DS touch screen

Hi guys.

I have used Nintendo DS touch screen in my project. But I have a problem which is I dont know coordinate when I touch the touch screen. I refer to some book. It said we can see it by using LCD . Is it the only way to see the exact coordinate we touch? Here is my coding. Thank you

// Power connections
#define Left 10 // Left (X1) to digital pin 8
#define Bottom 11 // Bottom (Y2) to digital pin 9
#define Right 12 // Right (X2) to digital pin 10
#define Top 13 // Top (Y1) to digital pin 11

// Analog connections
#define topInput A0 // Top (Y1) to analog pin 0
#define rightInput A1 // Right (X2) to analog pin 1

int coordX = 0, coordY = 0;

void setup()
{
Serial.begin(9600);
}

void loop()
{
if (touch()) // If screen touched, print co-ordinates
{
Serial.print(coordX);
Serial.print(" ");
Serial.println(coordY);
delay(250);
}
}

// return TRUE if touched, and set coordinates to touchX and touchY
boolean touch()
{
boolean touch = false;

// get horizontal co-ordinates
pinMode(Left, OUTPUT);
digitalWrite(Left, LOW); // Set Left to Gnd

pinMode(Right, OUTPUT); // Set right to +5v
digitalWrite(Right, HIGH);

pinMode(Top, INPUT); // Top and Bottom to high impedance
pinMode(Bottom, INPUT);

delay(3);
coordX = analogRead(topInput);

// get vertical co-ordinates
pinMode(Bottom, OUTPUT); // set Bottom to Gnd
digitalWrite(Bottom, LOW);

pinMode(Top, OUTPUT); // set Top to +5v
digitalWrite(Top, HIGH);

pinMode(Right, INPUT); // left and right to high impedance
pinMode(Left, INPUT);

delay(3);
coordY = analogRead(rightInput);

// if co-ordinates read are less than 1000 and greater than 0 then the screen has been touched
if(coordX < 1000 && coordX > 0 && coordY < 1000 && coordY > 0) {touch = true;}

return touch;
}