Water Supply I

const int ser = 8;
const int latch = 9;
const int clk = 10;
int Mandy [10] = {63, 5, 91, 79, 101, 110, 126, 7, 127, 103};
const int water = A0;
int waterSupply = 0;
int digit = 0;

void setup()
{
  pinMode (ser, OUTPUT);
  pinMode (latch, OUTPUT);
  pinMode (clk, OUTPUT);
  pinMode (water, INPUT);
  Serial.begin (9600);
}
l
void loop()
{
  waterSupply = analogRead (water);
  digit = map (waterSupply, 0, 300, 0, 9);
  digit = constrain (digit, 0, 9);
  Serial.println (waterSupply);
  switch (digit)
  {
    case 0:
    digitalWrite (latch, LOW);
    shiftOut (ser, clk, MSBFIRST, Mandy [0]);
    digitalWrite (latch, HIGH);
    break;
    case 1:
    digitalWrite (latch, LOW);
    shiftOut (ser, clk, MSBFIRST, Mandy [1]);
    digitalWrite (latch, HIGH);
    break;
    case 2:
    digitalWrite (latch, LOW);
    shiftOut (ser, clk, MSBFIRST, Mandy [2]);
    digitalWrite (latch, HIGH);
    break;
    case 3:
    digitalWrite (latch, LOW);
    shiftOut (ser, clk, MSBFIRST, Mandy [3]);
    digitalWrite (latch, HIGH);
    break;
    case 4:
    digitalWrite (latch, LOW);
    shiftOut (ser, clk, MSBFIRST, Mandy [4]);
    digitalWrite (latch, HIGH);
    break;
    case 5:
    digitalWrite (latch, LOW);
    shiftOut (ser, clk, MSBFIRST, Mandy [5]);
    digitalWrite (latch, HIGH);
    break;
    case 6:
    digitalWrite (latch, LOW);
    shiftOut (ser, clk, MSBFIRST, Mandy [6]);
    digitalWrite (latch, HIGH);
    break;
    case 7:
    digitalWrite (latch, LOW);
    shiftOut (ser, clk, MSBFIRST, Mandy [7]);
    digitalWrite (latch, HIGH);
    break;
    case 8:
    digitalWrite (latch, LOW);
    shiftOut (ser, clk, MSBFIRST, Mandy [8]);
    digitalWrite (latch, HIGH);
    break;
    case 9:
    digitalWrite (latch, LOW);
    shiftOut (ser, clk, MSBFIRST, Mandy [9]);
    digitalWrite (latch, HIGH);
    break;
  }

}