Switch in java

import java.util.Scanner;
public class MyClass {
    public static void main(String args[]) {
        Scanner reader = new Scanner(System.in);
        System.out.println("Enter a number: ");
        int x = reader.nextInt();
        System.out.println("Enter a second number: ");
        int y = reader.nextInt();
        System.out.println("Enter a operation symbole: ");
        char a = reader.nextChar();
        switch(a) {
            case '+':
                int z=a+b;
                System.out.println(x+a+y+"="+z);break;
            case '-':
                int z=a-b;
                System.out.println(x+a+y+"="+z);break;
            case '*':
                int z=a*b;
                System.out.println(x+a+y+"="+z);break;
            case '/':
                int z=a/b;
                System.out.println(x+a+y+"="+z);break;
            default:
                int z=a%b;
                System.out.println(x+a+y+"="+z);break;
        }
    }
}