kalkulator-1.java

import java.util.Scanner;

public class Kalkulator {
 public static void main(String args[]){
   double result = 0;
   Scanner scan = new Scanner(System.in);
   int bil1;
   char op, conf;
   System.out.print("Masukkan bilangan ke-1: ");
   bil1 = scan.nextInt();
   System.out.print("Masukkan operator (+, -, *, /): ");
   op = scan.next().charAt(0);
   System.out.print("Masukkan bilangan ke-2: ");
   int bil2 = scan.nextInt();

   result = Hitung(op, bil1, bil2);
   System.out.println(">> " + bil1 + " " + op + " " + bil2 + " = " + result);

   System.out.print("Lanjut (y/n) ? ");
   conf = scan.next().charAt(0);
   int count = 2;
   while(conf == 'y') {
     int bil_n;
     char op2;
     double tmp = result;
     System.out.println("Hasil terakhir: " + result);
     System.out.print("\nMasukkan operator (+, -, *, /): ");
     op2 = scan.next().charAt(0);
     count++;
     System.out.print("Masukkan bilangan ke-" + count + ": ");
     bil_n = scan.nextInt();
     result = Hitung(op2, result, bil_n);
     System.out.println(">> " + tmp + " " + op2 + " " + bil_n + " = " + result);

     System.out.print("Lanjut (y/n) ? ");
     conf = scan.next().charAt(0);
    }
  System.out.print("\nHasilnya: " + result);
  }

 public static double Hitung(char op, double bil1, double bil2) {
   double result = 0;
   switch(op) {
    case '+':
     result = bil1 + bil2;
     break;
    case '-':
     result = bil1 - bil2;
     break;
    case '*':
     result = bil1 * bil2;
     break;
    case '/':
     result = bil1 / bil2;
     break;
    default:
     break;
   }
  return result;
 }
}

kalkulator.java

import java.util.Scanner;

class Kalkulator {
    public static void main(String[] args) {

	Scanner scan = new Scanner(System.in);
        int nilai[] = new int[5];
        char[] operator = new char[5];
        int i = 0;
        char op;
		try{
			while(i < 5){ 
				nilai[i] = scan.nextInt();
				operator[i] =  (char) System.in.read();
				op = operator[i];
				if(op == '=') {
					break;
				}
				i++;
			}
        } catch (Exception e) {
            System.out.println("Error: " + e.toString());
        }

		int result = nilai[0];
		for (int start = 1; start <= i; start++) {
			if(operator[start-1] == '+') {
				result = result + nilai[start];
			}else if(operator[start-1] == '-') {
				result -= nilai[start];
			}else if(operator[start-1] == '/') {
				result /= nilai[start];
			}else if(operator[start-1] == '*') {
				result *= nilai[start];
			}
		}

		System.out.println("Hasilnya adalah : "+ result);
	}
}