/**
 *
 * @author Jorge Gonzalez  jorge_dan03@hotmail.com
 */
import javax.swing.JOptionPane;

public class Calculos{

    public static void main(String[] args) {
        String NUM, NUM1;
        float num, num1;
        String[] opciones = {"Suma",
            "Resta",
            "Multiplicación",
            "División",
            "Salir"};

        String op = "";
        do {
            op = (String) JOptionPane.showInputDialog(null, "Seleccione opción", "Calculos", -1, null, opciones, "Suma");
            if(op==null){
                op="";
            }
            switch (op) {
                case "Suma":
                    NUM = JOptionPane.showInputDialog(null, "Ingrese primer numero");
                    num = Float.parseFloat(NUM);
                    NUM1 = JOptionPane.showInputDialog(null, "Ingrese segundo numero");
                    num1 = Float.parseFloat(NUM1);
                    JOptionPane.showMessageDialog(null, num + " + " + num1 + " = " + (num + num1));
                    break;
                case "Resta":
                    NUM = JOptionPane.showInputDialog(null, "Ingrese primer numero");
                    num = Float.parseFloat(NUM);
                    NUM1 = JOptionPane.showInputDialog(null, "Ingrese segundo numero");
                    num1 = Float.parseFloat(NUM1);
                    JOptionPane.showMessageDialog(null, num + " - " + num1 + " = " + (num - num1));
                    break;
                case "Multiplicación":
                    NUM = JOptionPane.showInputDialog(null, "Ingrese primer numero");
                    num = Float.parseFloat(NUM);
                    NUM1 = JOptionPane.showInputDialog(null, "Ingrese segundo numero");
                    num1 = Float.parseFloat(NUM1);
                    JOptionPane.showMessageDialog(null, num + " x " + num1 + " = " + (num * num1));
                    break;
                case "División":
                    NUM = JOptionPane.showInputDialog(null, "Ingrese dividendo");
                    num = Float.parseFloat(NUM);
                    do{
                    NUM1 = JOptionPane.showInputDialog(null, "Ingrese divisor");
                    num1 = Float.parseFloat(NUM1);
                    if(num1==0){
                        JOptionPane.showMessageDialog(null, "El divisor debe ser > 0","Atención",2);
                    }
                    }while(num1==0);
                    JOptionPane.showMessageDialog(null, num + " / " + num1 + " = " + (num / num1));
                    break;

                case "Salir":
                    System.exit(0);
                    break;
                default :
                    JOptionPane.showMessageDialog(null,"Cancelado");
                    break;
           
            }

        } while (!op.equals("Salir")&&!op.equals(""));
    }
}