int pinA = 2;
int pinB = 3;
int pinC = 4;
int pinD = 5;
int pinE = 6;
int pinF = 7;
int pinG = 8;
int D1 =   9;
int D2 =  10;
int D3 =  11;
int D4 =  12;
int DP =  13;

// float to digit
const int digits = 4;
int digit[digits]; // array of digits for sevseg

void setup() {
  Serial.begin(115200);

  for (int i = 0; i < 12; i++)
    pinMode(i + 2, OUTPUT); // configure segment pins for output

  float f1 = 76.54;
  Serial.print(f1);
  Serial.println(" <-- Start with temperature/humidity as float with two decimal places. ");

  int i2 = f1 * 100;
  Serial.print(i2);
  Serial.println("  <-- Shift float left two decimal places ( * 100 ) to create an integer.");

  int i3 = (i2 % 10);
  Serial.print(i3);
  Serial.println("     <-- Apply \"modulus 10\" ( % 10 ) to integer to return units value.");

  int i4 = i2 / 10;
  Serial.print(i4);
  Serial.println("   <-- Shift integer right one decimal place ( / 10 ) to create new integer. ");

  for (int i = 0; i < digits; i++) {
    digit[i] = i2 % 10; // invert order for array
    i2 /= 10;
  }
  for (int i = 0; i < digits; i++) {
    Serial.print("Digit ");
    Serial.print(i);
    Serial.print(" = ");
    Serial.println(digit[i]); // show new digit order
  }
}

void loop() {
  // display_digit();
}

void display_digit() {
  for (int i = 0; i < digits; i++) {
    switch (2) {
      case 1: {
          digitalWrite(D1, LOW);
          digitalWrite(D2, HIGH);
          digitalWrite(D3, HIGH);
          digitalWrite(D4, HIGH);
          break;
        }
      case 2: {
          digitalWrite(D1, HIGH);
          digitalWrite(D2, LOW);
          digitalWrite(D3, HIGH);
          digitalWrite(D4, HIGH);
          break;
        }
      case 3: {
          digitalWrite(D1, HIGH);
          digitalWrite(D2, HIGH);
          digitalWrite(D3, LOW);
          digitalWrite(D4, HIGH);
          break;
        }
      case 4: {
          digitalWrite(D1, HIGH);
          digitalWrite(D2, HIGH);
          digitalWrite(D3, HIGH);
          digitalWrite(D4, LOW);
          break;
        }
      default: break;
    }

    switch (digit[0]) {
      case 0: {
          digitalWrite(pinA, HIGH);
          digitalWrite(pinB, HIGH);
          digitalWrite(pinC, HIGH);
          digitalWrite(pinD, HIGH);
          digitalWrite(pinE, HIGH);
          digitalWrite(pinF, HIGH);
          digitalWrite(pinG, LOW);
          break;
        }
      case 1: {
          digitalWrite(pinA, LOW);
          digitalWrite(pinB, HIGH);
          digitalWrite(pinC, HIGH);
          digitalWrite(pinD, LOW);
          digitalWrite(pinE, LOW);
          digitalWrite(pinF, LOW);
          digitalWrite(pinG, LOW);
          break;
        }
      case 2: {
          digitalWrite(pinA, HIGH);
          digitalWrite(pinB, HIGH);
          digitalWrite(pinC, LOW);
          digitalWrite(pinD, HIGH);
          digitalWrite(pinE, HIGH);
          digitalWrite(pinF, LOW);
          digitalWrite(pinG, HIGH);
          break;
        }
      case 3: {
          digitalWrite(pinA, HIGH);
          digitalWrite(pinB, HIGH);
          digitalWrite(pinC, HIGH);
          digitalWrite(pinD, HIGH);
          digitalWrite(pinE, LOW);
          digitalWrite(pinF, LOW);
          digitalWrite(pinG, HIGH);
          break;
        }
      case 4: {
          digitalWrite(pinA, LOW);
          digitalWrite(pinB, HIGH);
          digitalWrite(pinC, HIGH);
          digitalWrite(pinD, LOW);
          digitalWrite(pinE, LOW);
          digitalWrite(pinF, HIGH);
          digitalWrite(pinG, HIGH);
          break;
        }
      case 5: {
          digitalWrite(pinA, HIGH);
          digitalWrite(pinB, LOW);
          digitalWrite(pinC, HIGH);
          digitalWrite(pinD, HIGH);
          digitalWrite(pinE, LOW);
          digitalWrite(pinF, HIGH);
          digitalWrite(pinG, HIGH);
          break;
        }
      case 6: {
          digitalWrite(pinA, HIGH);
          digitalWrite(pinB, LOW);
          digitalWrite(pinC, HIGH);
          digitalWrite(pinD, HIGH);
          digitalWrite(pinE, HIGH);
          digitalWrite(pinF, HIGH);
          digitalWrite(pinG, HIGH);
          break;
        }
      case 7: {
          digitalWrite(pinA, HIGH);
          digitalWrite(pinB, HIGH);
          digitalWrite(pinC, HIGH);
          digitalWrite(pinD, LOW);
          digitalWrite(pinE, LOW);
          digitalWrite(pinF, LOW);
          digitalWrite(pinG, LOW);
          break;
        }
      case 8: {
          digitalWrite(pinA, HIGH);
          digitalWrite(pinB, HIGH);
          digitalWrite(pinC, HIGH);
          digitalWrite(pinD, HIGH);
          digitalWrite(pinE, HIGH);
          digitalWrite(pinF, HIGH);
          digitalWrite(pinG, HIGH);
          break;
        }
      case 9: {
          digitalWrite(pinA, HIGH);
          digitalWrite(pinB, HIGH);
          digitalWrite(pinC, HIGH);
          digitalWrite(pinD, LOW);
          digitalWrite(pinE, LOW);
          digitalWrite(pinF, HIGH);
          digitalWrite(pinG, HIGH);
        }
      default: break;
    }
  }
}