#include <Keypad.h>

#include <LiquidCrystal_I2C.h>

#include <Wire.h>



int trigPin =3;
int echoPin=2;
long duration;
float distance=0;
float R=0;
float H=0;
float V=0;
float v=0;
float L=0;
float S=0;
int M=0;
int N=0;
int W=0;
LiquidCrystal_I2C lcd(32,16,2);
const byte ROWS = 4;
const byte COLS = 4;
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {12, 11,10,9};
byte colPins[COLS] = {8, 7, 6,5};
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

void setup() {
  // put your setup code here, to run once:
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0,0);
  lcd.print("chose the form:");  
  // get the first number from the keypad
  lcd.setCursor(0,1);
  char key = keypad.waitForKey();
  while (key != '#') {
    if (key >= '0' && key <= '9') {
      M =M * 10 + (key - '0');
      
      lcd.print(key);
    }
    key = keypad.waitForKey();
  }
  lcd.clear();
  if(M>2 or M<1){ 
    lcd.setCursor(0,0);
  lcd.print("chose the form:");  
  // get the first number from the keypad
  lcd.setCursor(0,1);
  char key = keypad.waitForKey();
  while (key != '#') {
    if (key >= '0' && key <= '9') {
      M =M * 10 + (key - '0');
      
      lcd.print(key);
    }
    key = keypad.waitForKey();
  }
  lcd.clear();
  }
  while(M=2){
    lcd.print("cylinder");
    delay(1000);
    lcd.clear();  lcd.clear();
  lcd.print("enter radius:");
  
  // get the first number from the keypad
  lcd.setCursor(0,1);
  char key = keypad.waitForKey();
  while (key != '#') {
    if (key >= '0' && key <= '9') {
      R = R * 10 + (key - '0');
      
      lcd.print(key);
    }
    key = keypad.waitForKey();
  }
  
  // clear the LCD and display message for the second number
  lcd.clear();
  lcd.print("enter high:");
  
  // get the second number from the keypad
  lcd.setCursor(0,1);
  key = keypad.waitForKey();
  while (key != '#') {
    if (key >= '0' && key <= '9') {
      H = H * 10 + (key - '0');
     
      lcd.print(key);
    }
    key = keypad.waitForKey();
  }
  lcd.clear();
  break;
  }
  while(M=1){
    lcd.print("parallelogram");
    delay(1000);
    lcd.clear();
     lcd.setCursor(0,0);
    lcd.clear();
    lcd.print("enter width:");
    
    // get the first number from the keypad
    lcd.setCursor(0,1);
    char key = keypad.waitForKey();
    while (key != '#') {
      if (key >= '0' && key <= '9') {
        W = W * 10 + (key - '0');
        
        lcd.print(key);
      }
      key = keypad.waitForKey();
    }
    
    // clear the LCD and display message for the second number
    lcd.clear();
    lcd.print("enter high:");
    
    // get the second number from the keypad
    lcd.setCursor(0,1);
    key = keypad.waitForKey();
    while (key != '#') {
      if (key >= '0' && key <= '9') {
        H = H * 10 + (key - '0');
       
        lcd.print(key);
      }
      key = keypad.waitForKey();
    }
    lcd.clear();
        lcd.print("enter length:");
    
    // get the second number from the keypad
    lcd.setCursor(0,1);
    key = keypad.waitForKey();
    while (key != '#') {
      if (key >= '0' && key <= '9') {
        N = N * 10 + (key - '0');
       
        lcd.print(key);
      }
      key = keypad.waitForKey();
    }
    lcd.clear();

   break;
  }

}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration=pulseIn(echoPin,HIGH);
  if(duration==0){
    lcd.setCursor(0,0);
    lcd.print("no reading ");
  }
  else{
    distance=duration*0.034/2;
    if(M=1){
      v=3.14*(R*R)*(distance)*pow(10,-6);
      V=3.14*(R*R)*H*pow(10,-6);
      S=V-(v*1000);
      lcd.setCursor(0,0);
      lcd.print("volume (litre):");
      lcd.setCursor(0,1);
      lcd.print(S);
    }if(M=1){
      v=W*L*(distance)*pow(10,-6);
      v=W*L*H*pow(10,-6);
      S=v-(v*1000);
      lcd.setCursor(0,0);
      lcd.print("volume (litre):");
      lcd.setCursor(0,1);
      lcd.print(S);
      
    }
    
  }
}