full code:

import java.util.Scanner;

public class BasicCalculator {

static void main(String[] args){

Scanner scanner = new Scanner(System.in){

System.out.print( "Welcome to the java calc!" );

System.out.print( "enter the first number" );

final double num1 = scanner.nextDouble();

System.out.print("Enter an operator (+, -, *, /): ");

final char operator = scanner.next().charAt(0);

System.out.print("enter second number: ");

final double num2 = scanner.nextDouble();

double result;

switch (operator){

case '+':

result = num1 + num2;

System.out.println("Result: " + num1 + " + "+ num2 +" = "+ result );

break;

case '-':

result = num1 - num2;

System.out.println("Result: " + num1 + " - "+ num2 +" = "+ result );

break;

case '*':

result = num1 * num2;

System.out.println("Result: " + num1 + " * "+ num2 +" = "+ result );

break;

case '/':

if (num2 == 0) {

System.out.println("Error: Division by zero is not allowed.");

} else {

result = num1 / num2;

System.out.println("Result: " + num1 + " / "+ num2 +" = "+ result ) ;

break;

}

default:

System.out.println("Error: invalid operator entered");

break;

scanner.close();}

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

};

}}