calc avr

/*
 * Displays text sent over the serial port (e.g. from the Serial Monitor) on
 * an attached LCD.
 * YWROBOT
 *Compatible with the Arduino IDE 1.0
 *Library version:1.1
 */
#include <Wire.h> 
#include <math.h>
#include <LiquidCrystal_I2C.h>
#include <Keypad.h>

long first = 0;
long second = 0;
double total = 0;

char customKey;

int menuFlag=0;
int menuPosition=0;
int needToClear=0;

const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns
//define the cymbols on the buttons of the keypads
char hexaKeys[ROWS][COLS] = {
  {'+','3','2','1'},
  {'-','6','5','4'},
  {'*','9','8','7'},
  {'/','=','0','C'}
};
byte rowPins[ROWS] = {1,2,3,4}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {8,7,6,5}; //connect to the column pinouts of the keypad
char string[500]="Nedavno prochital ochen' interesnuju stat'ju pro obrabotku 50 gigabit/s na servere i vspomnil, chto u menja v chernovikah lezhit stat'ja pro to, kak my god nazad razrabatyvali sistemu monitoringa video-potokov s obshhim ob#jomom trafika do 100 Gbit/s.";
char showString[16];
char showString2[16];
int currentStringPos;

Keypad keypad = Keypad( makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS );
byte ledPin = 13; 

boolean blink = false;
boolean ledPin_state;
///////////////////////////////////////////////////////////////
int miFlag=0;
int charBuff=0;
int  buff[200];
int  buffTail;
int  buffCurrent;

///////////////////////////////Буффер для ввода нового числа///////////////////////////
long inputBuff;

///////////////////////////////////////////////////////////////////////////////////////

LiquidCrystal_I2C lcd(0x27,16,2);  // set the LCD address to 0x27 for a 16 chars and 2 line display

void makePrintStr(int currentStringPos){
    for(int i=0;i<16;i++){
        showString[i]=string[currentStringPos*16+i];
        showString2[i]=string[(currentStringPos+1)*16+i];
    }
}


void setup()
{
  lcd.init();                      // initialize the lcd 
  lcd.backlight();
  Serial.begin(9600);
  lcd.print('>');
   pinMode(ledPin, OUTPUT);              // Sets the digital pin as output.
    digitalWrite(ledPin, HIGH);           // Turn the LED on.
    ledPin_state = digitalRead(ledPin);   // Store initial LED state. HIGH when LED is on.
    keypad.addEventListener(keypadEvent); // Add an event listener for this keypad
}

void showPosName(){
    lcd.clear();
    if(menuPosition==1){
        lcd.print("Calculator");
    }
    if(menuPosition==2){
        lcd.print("Reader");
    }
    if(menuPosition==3){
        lcd.print("SIN");
    }
    if(menuPosition==4){
        lcd.print("COS");
    }
    needToClear=1;
}


long inputNumber()
{
  while( 1 )
  {
    customKey = keypad.getKey();
    if(customKey >= '0' && customKey <= '9')
    {
      inputBuff = inputBuff * 10 + (customKey - '0');
      lcd.clear();
      lcd.print(inputBuff);
      lcd.setCursor(0,1);
       if(menuPosition==3){
            lcd.print("SIN=");
            lcd.print(sin(inputBuff*3.14/180));
        }
        if(menuPosition==4){
            lcd.print("COS=");
            lcd.print(cos(inputBuff*3.14/180));
        }
      }
  
    if((customKey == '=')||(customKey == 'C') ) break;  //return second;
  }
 return inputBuff; 
}

long SecondNumber()
{
  while( 1 )
  {
    customKey = keypad.getKey();
    if(customKey >= '0' && customKey <= '9')
    {
      second = second * 10 + (customKey - '0');
      lcd.print(customKey);
    }

    if(customKey == '=') break;  //return second;
  }
 return second; 
}


 void simpleCalc(char customKey){
     switch(customKey) 
  {
  case '0' ... '9': // This keeps collecting the first value until a operator is pressed "+-*/"
    lcd.setCursor(0,0);
    first = first * 10 + (customKey - '0');
    lcd.print(first);
    break;

  case '+':
    first = (total != 0 ? total : first);
    lcd.print("+");
    second = SecondNumber(); // get the collected the second number
    total = first + second;
    lcd.setCursor(0,1);
    lcd.print(total);
    total = 0;
    first = 0, second = 0; // reset values back to zero for next use
    needToClear=1;
    break;

  case '-':
    first = (total != 0 ? total : first);
    lcd.print("-");
    second = SecondNumber();
    total = first - second;
    lcd.setCursor(0,1);
    lcd.print(total);
    needToClear=1;
    total = 0;
    first = 0, second = 0;
    break;

  case '*':
    first = (total != 0 ? total : first);
    lcd.print("*");
    second = SecondNumber();
    total = first * second;
    lcd.setCursor(0,1);
    lcd.print(total);
    needToClear=1;
    total = 0;
    first = 0, second = 0;
    break;

  case '/':
    first = (total != 0 ? total : first);
    lcd.print("/");
    second = SecondNumber();
    lcd.setCursor(0,1);

    second == 0 ? lcd.print("Invalid") : total = (float)first / (float)second;

    lcd.print(total);
    first = 0, second = 0;
    total = 0;
    needToClear=1;
    break;

  case 'C':
    total = 0;
    first = 0, second = 0;
    lcd.clear();
    break;
  }
 }

void reader(){
  
  makePrintStr(currentStringPos);
  lcd.clear();
  lcd.print(showString);
  lcd.setCursor(0,1);
  lcd.print(showString2);
}
long res;
void loop(){
    char key = keypad.getKey();
    if (key) {
        if(needToClear){
            lcd.clear();
            needToClear=0;
        }
        if(menuFlag==0){
            if(menuPosition==1){
                simpleCalc(key);    
            }
            else if((menuPosition==3)||(menuPosition==4)){
                res=inputNumber();
                inputBuff=0;
                lcd.clear();
            }
        }
        
  
        Serial.print(key);
    }
       
    
    if(key=='/') {
        if(menuFlag==1){
            menuPosition++;
            lcd.clear();
            lcd.print("Position ");
            lcd.print(menuPosition);
            showPosName();
        }
        else if(menuFlag==0){
            if(menuPosition==2){
                currentStringPos+=2;
                reader();
            }
        }
    }
    else if(key=='*') {
        if(menuFlag==1){
            if(menuPosition>0) menuPosition--;
            lcd.clear();
            lcd.print("Position ");
            lcd.print(menuPosition);
            showPosName();
        }
        else if(menuFlag==0){
            if(menuPosition==2){
                if(currentStringPos>1) currentStringPos-=2;
                reader();
            }
        }
    }
    if (blink){
        digitalWrite(ledPin,!digitalRead(ledPin));    // Change the ledPin from Hi2Lo or Lo2Hi.
        delay(100);
    }
}

// Taking care of some special events.
void keypadEvent(KeypadEvent key){
    switch (keypad.getState()){
    case PRESSED:
        
        break;

    case RELEASED:
        if (key == 'C') {
            digitalWrite(ledPin,ledPin_state);    // Restore LED state from before it started blinking.
            blink = false;
        }
        break;

    case HOLD:
    if (key=='C') {
        lcd.clear();
        if(menuFlag==0){
            lcd.print("menu mode on");
            needToClear=1;
            menuFlag=1;
        }  
        else if(menuFlag==1){
            lcd.print("menu mode off");
            needToClear=1;
            menuFlag=0;
        }
    }
     
    if (key == '=') {
            digitalWrite(ledPin,!digitalRead(ledPin));
            ledPin_state = digitalRead(ledPin);        // Remember LED state, lit or unlit.
            lcd.clear();
            menuPosition=1;
            menuFlag=0;
            lcd.print("0");
    }   
    
    
        break;
    }
}