Split string calculator

[zakratcliffe]

I have this code

 
    import java.util.Scanner;
public class Calculator {
 
    public static void main(String[] args) {
 
          Scanner scan = new Scanner(System.in) ;
          System.out.println("Enter your two numbers and the operation with spaces between e.g 8 9 -");
 
          String calculation=scan.nextLine();
 
          String [] parts = calculation.split(" ");
 
           //Add
            if (parts[2].equals("+")) {
                String ans = parts[0] + parts[1];
            }
 
            //Subtract
            else if (parts[2].equals("-")) {
                String ans = parts[0] - parts[1];
            }
 
            //Multiply
            else if (parts[2].equals("*")) {
                String ans = parts[0] * parts[1];
            }
 
            //Divide
            else if (parts[2].equals("/")) {
                String ans = parts[0] / parts[1];
            }
 
    }
 
}
 

the error is within the if statements regarding -, * and / operations "The operator / is undefined for the argument type(s) java.lang.String, java.lang.String" can anyone help

[chaarmann]

"parts" is an array of Strings, not numbers!
You cannot subtract/divide/multiply strings, so you have to convert it to a number before:

String s="12";
int i = Integer.parseInt(s);

Remark: you can add strings, but this is the concat operation. So "1"+"2" would give you "12" and not 3!

Also, the result of dividing an int with another int gives you an int, not a String.
You can convert the result to a String using the valueOf() method.
So in your case, change line 31 to:

String ans = String.valueOf(Integer.parseInt(parts[0]) / Integer.parseInt(parts[1]));