Exercises: Calculator

Write a program that emulates a calculator. It’s a more complete exercise to what was presented previously.

It should support:

• + (addition)
• - (subtraction)
• * (multiplication)
• / (division)

It accepts the operands and the operation on multiple lines.

Input:
3
*
2
Output: 3 * 2 = 6

Hint:

// String comparison works like this:
Scanner scanner = new Scanner(System.in);
String a = scanner.next();

if (a.equals("hello")) {
    System.out.println("Are equal");
}

if ("hello".equals(a)) {
    System.out.println("Are equal");
}

More features:

1. Add looping to the calculator. Instead of exiting after the calculation it should ask the user if they want to continue or quit. If the user enters quit the program stops.
2. Handle division by zero. As you might have noticed an input of 2/0 crashes the program. Handle that case.
3. DIFFICULT / EXTRA Give the user the possibility to use the last result as one of the values in the next calculation.

Input:
3
*
2
Output: 3 * 2 = 6
Input:
last
*
2
Output: 12

Hint:

// How to convert a string to an integer
String a = "42";
int b = Integer.parseInt(a);