//the curcuit is a 5 by 3 led matrix
//all of the cathodes in a column and all of the anodes in a row are connected together to pins

#define column_num 3 //number of columns
#define row_num 5 //number of rows

int column_pin[column_num] = {2, 3, 4};//cathodes in a column conected to these pin
int row_pin[row_num] = {5, 6, 7, 8, 9};//anodes in a row connected to these pins
int column_pot = A1;
int row_pot = A0;

int row, column;//holds the index for row and column

// variables for function
int count = 0;
float division, comp_value;

void setup() {
  for (int i = 0; i < row_num; i++) {
    pinMode(row_pin[i], OUTPUT);
  }

  for (int i = 0; i < column_num; i++) {
    pinMode(column_pin[i], OUTPUT);
  }

  pinMode(row_pot, INPUT);
  pinMode(column_pot, INPUT);
}

//lights the led specified by row and column
void show(int row, int column) {
  //each led's anode is connected to row_pin and cathode is connected to column_pin
  //for it to light up the row_pin must be high and column_pin must be low
  for (int i = 0; i < row_num; i++) {
    //loop through the rows and only set the specified pin high
    if (i == row) {
      digitalWrite(row_pin[i], HIGH);
    }
    else {
      //set all other pins to low
      digitalWrite(row_pin[i], LOW);
    }
  }

  for (int i = 0; i < column_num; i++) {
    //loop through the colum and set the specified column low
    if (i == column) {
      digitalWrite(column_pin[i], LOW);
    }
    else {
      //set all other pins to high
      digitalWrite(column_pin[i], HIGH);
    }
  }
}

//retruns a value for row or column based on the analog value given
int give_position(int value, float num) {
  //number of rows or column is also needed to divide the pot into appropriate sections
  count = 0;
  division = 1023 / num;//here 1023 is divided
  comp_value = division;//comparison value
  while (comp_value != 1023) {
    //add the comp_value by division and maintain count until we get to 1023
    //if comp_value is greater than analog value return the number of time division had to be added (count)
    if (comp_value >= value) {
      return count;
    }
    comp_value += division;
    count++;
  }
}

void loop() {
  row = give_position(analogRead(row_pot), row_num);
  column = give_position(analogRead(column_pot), column_num);
  show(row, column);
}