Javascript program to make a simple calculator

We are going to make a simple calculator in Javascript. We will use two methods one is by using an if-else statement and another is a switch case statement.

Let’s see the code using the if-else statement.

let number1 = 10, number2 = 2, res;
let op = prompt("Enter an operator(+,-,*,/):")

if (op == '+')
  {
    res = number1 +  number2;
    console.log("The sum is "+res);
  }
else if (op == '-')
{
    res = number1 -  number2
  console.log("The substraction is "+res);
}
else if (op == '*')
{
    res = number1 *  number2
  console.log("The multiplication is"+res);
}
else
{
    res = number1 /  number2
  console.log("The division is"+res);
}

The output of the code is

Enter an operator(+,-,*,/): +
The sum is 12

Enter an operator(+,-,*,/): -
The substraction is 8

Enter an operator(+,-,*,/): *
The multiplication is 20

Enter an operator(+,-,*,/): /
The division is 5

Let’s see the second method using switch case statement

let number1 = 10, number2 = 2, res;
let op = prompt("Enter an operator(+,-,*,/)")

switch(op)
  {
    case '+':
      res = number1 +  number2;
      console.log("The sum is "+res);
      break;
      
    case '-':
      res = number1 -  number2
      console.log("The substraction is "+res);
      break;
      
    case '*':
      res = number1 *  number2
      console.log("The multiplication is"+res);
      break;
      
    case '/':
      res = number1 /  number2
      console.log("The division is"+res);
      break;
  }

The output of the code is

Enter an operator(+,-,*,/): +
The sum is 12

Enter an operator(+,-,*,/): -
The substraction is 8

Enter an operator(+,-,*,/): *
The multiplication is 20

Enter an operator(+,-,*,/): /
The division is 5