Sample I/O for HW2

Following is a sample session with the Perl Calculator you will write. (What the user types is in bold print)

~lallip (1) PerlCalc.pl
Enter a formula, or 'done' to quit:
5 + 4 =
9
Enter a formula, or 'done' to quit:
6* 3 = 
18
Enter a formula, or 'done' to quit:
-4 - 20=
-24
Enter a formula, or 'done' to quit:
-2=
That is not a valid formula.  Try again
4 + 5
That is not a valid formula.  Try again
10/3 = 
3
Enter a formula, or 'done' to quit:
10.0 / 3 = 
3.33333333333333333
Enter a formula, or 'done' to quit:
10+50.3=
60.3
Enter a formula, or 'done' to quit:
-2 * -10 = 
20
Enter a formula, or 'done' to quit:
20 % 6 = 
2
Enter a formula, or 'done' to quit:
foobar
That is not a valid formula.  Try again
done

The formulas entered (sorted by operation, then result) are:
10+50.3= 60.3
5 + 4 = 9
-2 * -10 = 20
6* 3 = 18
-4 - 20= -24
10.0 / 3 = 3.33333333333333333
10/3 = 3
20 % 6 = 2

~lallip (2)