READ-EVAL-PRINT-LOOP

Write a simple REPL program (Read–Eval–Print–Loop).

Take a formula from a user then print out the result. The formula must be in this format:

<first number> <arithmetic: + - * / > <second number>

Example:

> 1 + 2

1 + 2 = 3

> 2 * 10

2 * 10 = 20