import javax.swing.*;

public class Calculator3 {
    public static void main(String[] args) {

	String tmp1; double v1; // 1st user-entered value
	String tmp2; double v2; // 2nd user-entered value
	String op;              // desired operation
	double result = 0 ;     // desired result of v1+v2

	// Obtain user input:
	tmp1 = JOptionPane.showInputDialog("Enter 1st value:");
	tmp2 = JOptionPane.showInputDialog("Enter 2nd value:");
	op   = JOptionPane.showInputDialog("Enter operation:");
	
	// Convert input to numbers:
	v1 = Double.parseDouble(tmp1);
	v2 = Double.parseDouble(tmp2);

	// Perform operation:
	if (op.equals("+"))
	    result = v1+v2;
	else if (op.equals("-"))
	    result = v1-v2;
	else if (op.equals("*"))
	    result = v1*v2;
	else if (op.equals("/"))
	    result = v1/v2;
	else {
	    JOptionPane.showMessageDialog(null, "Unknown operator!");
	    System.exit(0);
	}

	// Output result:
	JOptionPane.showMessageDialog(null, "Result: "+result);

    }
}