AR-AD2: Arduino Advanced Calculator

To work on this project, just connect Arduino UNO with data cable to your PC or laptop. Then upload the given program in it. Press Ctrl-Shift-M to open Serial Monitor window. Enter two numbers with required mathematical operator, and press Enter.

Examples

1. Type 3+5 and press Enter to get the answer.
2. Type 36/3 and press Enter to get the answer.
3. Type 785*562348 and press Enter to get the answer.
4. Type 574-394 and press Enter to get the answer.

/*
 * Calculator using Arduino
 * Designed by Vidyasagar Academy, Akola
 * Date: 04.08.2020
 * www.vsa.edu.in 
 */

int first_number; // the first number variable in calculations
int second_number; // the second number variable in calculations
char math_operator; // create a char variable to store the calculated value
int answer; // the answer of the calculation

/*  ***** IMPORTANT NOTE *****
* This calculator can calculate only the integer values.
* This calculator can calculate only two numbers at its input, for example:
* 2+2 is allowed, but 2+2+2+2 is not allowed.
*/

void setup() 
{
  Serial.begin(9600); // begins serial communications
  Serial.println("Welcome to my calculator...!");
  Serial.println("Ready to Calculate...");
  Serial.println(" ");
}

void loop() 
{
  while(Serial.available() > 0) 
  {    
    first_number = Serial.parseInt();    
    math_operator = Serial.read();     
    second_number = Serial.parseInt();  
    calculate(); // user defined function to perform the calculations 
    Serial.print(first_number);
    Serial.print(" "); // create one space after first number
    Serial.print(math_operator);
    Serial.print(" "); // create one space after operator
    Serial.print(second_number);
    Serial.print(" = ");
    Serial.println(answer); // Prints the answer of the calculation
    Serial.println("Ready to calculate next...");
    delay(1000);
  }
}

void calculate() 
{ 
  // Custom function that performs the calculations  

  if (math_operator == '+') // character literal (see bottom note)
  {
    answer = first_number + second_number;
  }

  else if (math_operator == '-')  
  {
    answer = first_number - second_number; 
  }

  else if (math_operator == '*')  
  {
    answer = first_number * second_number; 
  }

  else if (math_operator == '/')  
  {
    answer = first_number / second_number; 
  }
}

/*
Literals or constants are the values we write in a conventional form 
whose value is obvious. In contrast to variables, 
literals (123, 4.3, "hi") do not change in value. 
These are also called explicit constants or manifest constants.
In C and in C++ single quotes identify a single character, 
while double quotes create a string literal. 
'a' is a single a character literal, while "a" is a string literal 
containing an 'a' and a null terminator (that is a 2 char array).
 */