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

In this article, we will understand how to construct a simple calculator using switch-case. The switch statement evaluates an expression, matching the expression's value to a case clause, and executes statements associated with that case.

Following are the arithmetic operations we are going to perform.

• Subtraction
• Multiplication
• Division
• Floor Division
• Modulo

Below is a demonstration of the same −

Input

Suppose our input is −

The two inputs: 40.0 and 12.0
Operator:%

Output

The desired output would be −

The result is 40.0 % 12.0 = 4.0

## Algorithm

Step 1 - START
Step 2 - Declare three values namely my_input_1, my_input_2 and my_result and declare a character value namely operator.
Step 3 - Read the required values from the user/ define the values
Step 4 - Define case statements which takes ‘operator’ value as switch case to calculate the sum, difference, multiplication, division, modulus.
Step 5 - Pass the operator value to the case statements to calculate the arithmetic operation between the two inputs ‘my_input_1’ and ‘my_input_2’
Step 7 - Display the result
Step 8 - Stop

## Example 1

Here, the input is being entered by the user based on a prompt. You can try this example live in ourcoding ground tool .

import java.util.Scanner;
public class OperatorSwitch {
public static void main(String[] args) {
char operator;
Double my_input_1, my_input_2, my_result;
System.out.println("Required packages have been imported");
Scanner my_scanner = new Scanner(System.in);
System.out.println("A reader object has been defined ");
System.out.println("Enter the first number");
my_input_1 = my_scanner.nextDouble();
System.out.println("Enter the second number");
my_input_2 = my_scanner.nextDouble();
System.out.println("Enter any of the following operator: +, -, *, /, %");
operator = my_scanner.next().charAt(0);
switch (operator) {
case '+':
my_result = my_input_1 + my_input_2;
System.out.println(my_input_1 + " + " + my_input_2 + " = " + my_result);
break;
case '-':
my_result = my_input_1 - my_input_2;
System.out.println(my_input_1 + " - " + my_input_2 + " = " + my_result);
break;
case '*':
my_result = my_input_1 * my_input_2;
System.out.println(my_input_1 + " * " + my_input_2 + " = " + my_result);
break;
case '/':
my_result = my_input_1 / my_input_2;
System.out.println(my_input_1 + " / " + my_input_2 + " = " + my_result);
break;
case '%':
my_result = my_input_1 % my_input_2;
System.out.println(my_input_1 + " % " + my_input_2 + " = " + my_result);
break;
default:
System.out.println("The operator you have selected is invalid");
break;
}
}
}

## Output

Required packages have been imported
A reader object has been defined
Enter the first number
40
Enter the second number
12
Choose any of the following operator: +, -, *, /, %
%
40.0 % 12.0 = 4.0

## Example 2

Here, the integer has been previously defined, and its value is accessed and displayed on the console.

public class OperatorSwitch {
public static void main(String[] args) {
char operator;
Double my_input_1, my_input_2, my_result;
my_input_1 = 40.0;
my_input_2 = 12.0;
operator = '%';
System.out.println("The two numbers are defined as " +my_input_1 +" and " +my_input_2);
System.out.println("The operator is defined as " +operator);
switch (operator) {
case '+':
my_result = my_input_1 + my_input_2;
System.out.println(my_input_1 + " + " + my_input_2 + " = " + my_result);
break;
case '-':
my_result = my_input_1 - my_input_2;
System.out.println(my_input_1 + " - " + my_input_2 + " = " + my_result);
break;
case '*':
my_result = my_input_1 * my_input_2;
System.out.println(my_input_1 + " * " + my_input_2 + " = " + my_result);
break;
case '/':
my_result = my_input_1 / my_input_2;
System.out.println(my_input_1 + " / " + my_input_2 + " = " + my_result);
break;
case '%':
my_result = my_input_1 % my_input_2;
System.out.println(my_input_1 + " % " + my_input_2 + " = " + my_result);
break;
default:
System.out.println("The operator you have selected is invalid");
break;
}
}
}

## Output

The two numbers are defined as 40.0 and 12.0
The operator is defined as %
40.0 % 12.0 = 4.0