obichamvlado

#include <Arduino.h>

#define LEDred       2
#define LEDgreen     4
#define numberLength 20  //How long the 2 numbers can be - 20 in this case. Please change only this number if bigger numbers are needed.

char firstNumber[numberLength];
int firstNumberCount = 1;
int firstNumberAsInt = 0;
char secondNumber[numberLength];
int secondNumberCount = 1;
int secondNumberAsInt = 0;
bool first = true;
bool second = false;
int result = 0;


void setup() {
  Serial.begin(9600);
  pinMode(LEDred, OUTPUT);
  pinMode(LEDgreen, OUTPUT);
  firstNumber[0] = 0;
  secondNumber[0] = 0;
}

void loop() {
  int charsRead = 0;
  while(Serial.available() > 0)
  {
    char c = Serial.read();
    if(c != '\n')
    {
      digitalWrite(LEDgreen, LOW);
      digitalWrite(LEDred, LOW);
      if(c == '0' || c == '1' || c == '2' || c == '3' || c == '4' || c == '5' || c == '6' || c == '7' || c == '8' || c == '9')
      {
        if(first)
        {
          firstNumber[charsRead] = c;
          charsRead++;
          firstNumberCount = charsRead;
        }
        else if (second)
        {
          secondNumber[charsRead] = c;
          charsRead++;
          secondNumberCount = charsRead;
        }
      }
      else if (c == '+' || c == '-' || c == '*' || c == '/')
      {
        switch(c)
        {
          case '+':
          //code for addition and converting the arrays into integers
          first = false;
          second = true;
          for(int i = 0; i < firstNumberCount; i++)
          {
            int integ = ((int)(firstNumber[i]) - 48) * pow((1*10),(firstNumberCount-i)); // na stepen count - i ??? kak e na stepen v C, da proverq formulata na vladan da kaja na vladan che atof e cheating
            firstNumberAsInt += integ;
          }
          for(int i = 0; i < secondNumberCount; i++)
          {
            int integ = ((int)(secondNumber[i]) - 48) * pow((1*10),(secondNumberCount-i)); // na stepen count - i ??? kak e na stepen v C, da proverq formulata na vladan da kaja na vladan che atof e cheating
            secondNumberAsInt += integ;
          }
          result = firstNumberAsInt + secondNumberAsInt;
          break;

          case '-':
          //code for substraction and converting the arrays into integers
          first = false;
          second = true;
          for(int i = 0; i < firstNumberCount; i++)
          {
            int integ = ((int)(firstNumber[i]) - 48) * pow((1*10),(firstNumberCount-i)); // na stepen count - i ??? kak e na stepen v C, da proverq formulata na vladan da kaja na vladan che atof e cheating
            firstNumberAsInt += integ;
          }
          for(int i = 0; i < secondNumberCount; i++)
          {
            int integ = ((int)(secondNumber[i]) - 48) * pow((1*10),(secondNumberCount-i)); // na stepen count - i ??? kak e na stepen v C, da proverq formulata na vladan da kaja na vladan che atof e cheating
            secondNumberAsInt += integ;
          }
          result = firstNumberAsInt - secondNumberAsInt;
          break;

          case '*':
          //code for multiplying and converting the arrays into integers
          first = false;
          second = true;
          for(int i = 0; i < firstNumberCount; i++)
          {
            int integ = ((int)(firstNumber[i]) - 48) * pow((1*10),(firstNumberCount-i)); // na stepen count - i ??? kak e na stepen v C, da proverq formulata na vladan da kaja na vladan che atof e cheating
            firstNumberAsInt += integ;
          }
          for(int i = 0; i < secondNumberCount; i++)
          {
            int integ = ((int)(secondNumber[i]) - 48) * pow((1*10),(secondNumberCount-i)); // na stepen count - i ??? kak e na stepen v C, da proverq formulata na vladan da kaja na vladan che atof e cheating
            secondNumberAsInt += integ;
          }
          result = firstNumberAsInt * secondNumberAsInt;
          break;

          case '/':
          //code for dividing and converting the arrays into integers
          first = false;
          second = true;
          for(int i = 0; i < firstNumberCount; i++)
          {
            int integ = ((int)(firstNumber[i]) - 48) * pow((1*10),(firstNumberCount-i)); // na stepen count - i ??? kak e na stepen v C, da proverq formulata na vladan da kaja na vladan che atof e cheating
            firstNumberAsInt += integ;
          }
          for(int i = 0; i < secondNumberCount; i++)
          {
            int integ = ((int)(secondNumber[i]) - 48) * pow((1*10),(secondNumberCount-i)); // na stepen count - i ??? kak e na stepen v C, da proverq formulata na vladan da kaja na vladan che atof e cheating
            secondNumberAsInt += integ;
          }
          result = firstNumberAsInt / secondNumberAsInt;
          break;
        }
      }
      if(c == '=')
      {
        first = true;
        second = false;
        firstNumber[0] = 0;
        secondNumber[0] = 0;
        firstNumberCount = 1;
        secondNumberCount = 1;
        firstNumberAsInt = 0;
        secondNumberAsInt = 0;
        //reseting everything, printing result.
        Serial.print("Result is: "); Serial.println(result);
        //make LEDS light up
        if(result > 0)
        digitalWrite(LEDgreen, HIGH);
        else if (result < 0)
        digitalWrite(LEDred, HIGH);
        else
        {
          digitalWrite(LEDgreen, LOW);
          digitalWrite(LEDred, LOW);
        }
        result = 0;
      }
    }
  }
}