Simple Calculator

Hi everyone!

I'm programming a simple calculator and this is my first time programming. I'm having a bit of difficulty on figuring out this assignment. Everything is working correctly except I need to have the console ask the user if he would like to rerun the program. When the user inputs, "yes" it should start again from the beginning. This is the code I have so far. Do I need to nest all of this code into another loop statement?

Code Java:

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import java.util.*;
import javax.swing.*;
 
public class SimpleCalculator {
	public static void main (String [] args){
		double result = 0.0, temp = result, oldResult = result;
 
		Scanner input = new Scanner(System.in);
 
		//Initialization of Calculator
		System.out.println("Calculator is on");
		System.out.println("result = " + result);
 
		//Calculations
		String operation = "";
		while (!operation.equals("R") && !operation.equals("r")) {
			operation = input.nextLine();
 
			//Read operator
			char sign = operation.charAt(0);
 
			//Addition, Subtraction, Multiplication, Division
			switch (sign){
			case '+': temp = Double.parseDouble(operation.substring(1));
					  oldResult = result;
					  result = result + temp;
					  System.out.println(oldResult + " + " + temp + " = " + result);
					  break;
			case '-': temp = Double.parseDouble(operation.substring(1));
					  oldResult = result;
					  result = result - temp;
					  System.out.println(oldResult + " - " + temp + " = " + result);
			  		  break;
			case '*': temp = Double.parseDouble(operation.substring(1));
					  oldResult = result;
					  result = result * temp;
					  System.out.println(oldResult + " * " + temp + " = " + result);
					  break;
			case '/': temp = Double.parseDouble(operation.substring(1));
					  oldResult = result;
					  result = result / temp;
					  System.out.println(oldResult + " / " + temp + " = " + result);
	  		          break;
			case 'r': break;
			case 'R': break;
			default: System.out.println(sign + " is an unknown operation");
					 System.out.println("Reenter your last line: ");
 
			}
 
			//END
		}	
 
 
		//Printing of Result
		System.out.println("Final result = " + result);
 
		//Again Method
		System.out.println("Again?");
		String again = input.nextLine();
 
 
		}
 
 
}

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This would best be handled with a do while loop.
Yes, you would have to enclose the code you want within the loop. while and do-while statements

you could also use a SENTINEL constant value that the user can type to escape the loop. make another switch statement after the

Code :

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System.out.println("Again?");
String again = input.nextLine();

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that would continue for yes(say !(operation.equals(r)) again, which will reiterate the loop) for no, say operation.equals(r) is true, and the SENTINEL value could be 0 or q or something, which would also exit the loop.

add a Do-While Statement into your code and then run your code. It will work as you want it to.