 # Java Program to Make a Simple Calculator Using switch...case

To understand this example, you should have the knowledge of the following Java programming topics:

## Example: Simple Calculator using Java switch Statement

``````import java.util.Scanner;

class Main {
public static void main(String[] args) {

char operator;
Double number1, number2, result;

// create an object of Scanner class
Scanner input = new Scanner(System.in);

// ask users to enter operator
System.out.println("Choose an operator: +, -, *, or /");
operator = input.next().charAt(0);

// ask users to enter numbers
System.out.println("Enter first number");
number1 = input.nextDouble();

System.out.println("Enter second number");
number2 = input.nextDouble();

switch (operator) {

case '+':
result = number1 + number2;
System.out.println(number1 + " + " + number2 + " = " + result);
break;

// performs subtraction between numbers
case '-':
result = number1 - number2;
System.out.println(number1 + " - " + number2 + " = " + result);
break;

// performs multiplication between numbers
case '*':
result = number1 * number2;
System.out.println(number1 + " * " + number2 + " = " + result);
break;

// performs division between numbers
case '/':
result = number1 / number2;
System.out.println(number1 + " / " + number2 + " = " + result);
break;

default:
System.out.println("Invalid operator!");
break;
}

input.close();
}
}``````

Output 1

```Choose an operator: +, -, *, or /
*
Enter first number
3
Enter second number
9
3.0 * 9.0 = 27.```

Here, we have used the `Scanner` class to take 3 inputs from the user.

• operator - specifies the operation to be performed
• number1/number2 - operands to perform operation on

Since the operator matches the `case '*'`, so the corresponding codes are executed.

``````result = number1 * number2;
System.out.println(number + " * " + number2 + " = " + result);
break;``````

These statements compute the product of two numbers and print the output. Finally, the break statement ends the switch statement.

Similarly, for different operators, different cases are executed.

Output 2

```Choose an operator: +, -, *, or /
+
Enter first number
21
Enter second number
8
21.0 + 8.0 = 29.0```

Output 3

```Choose an operator: +, -, *, or /
-
Enter first number
9
Enter second number
3
9.0 - 3.0 = 6.0```

Output 4

```Choose an operator: +, -, *, or /
/
Enter first number
24
Enter second number
8
24.0 / 8.0 = 3.0```