Source code java aplikasi Kalkulator versi Switch case

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package kalkulator;

import java.io.DataInputStream;
import java.io.IOException;
import java.util.Scanner;

/**
 *
 * @author gaara
 */
public class Kalkulator {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws IOException {
        // TODO code application logic here
        Scanner masuk = new Scanner(System.in);
        DataInputStream msk = new DataInputStream(System.in);
        double nilai_1, nilai_2;
        double hasil=0;
        char operator;


        System.out.println("====================");
        System.out.println("aplikasi kalkulator");
        System.out.println("====================");

        System.out.print("masukan nilai 1 : ");
        nilai_1 = masuk.nextInt();

        System.out.print("masukan nilai 2 : ");
        nilai_2 = masuk.nextInt();

        System.out.print("masukan operator : ");
        operator = (char) msk.read();

        switch (operator) {
            case '+':
                hasil = nilai_1 + nilai_2;
                break;
            case '-':
                hasil = nilai_1 - nilai_2;
                break;
            case '*':
                hasil = nilai_1 * nilai_2;
                break;
            case '/':
                hasil = nilai_1 / nilai_2;
                break;
            default:
                System.out.println("maaf anda kurang bejo");
               

        }                System.out.println("jadi hasilnya : " + nilai_1 + operator + nilai_2 + '=' + hasil);
    }
}