Simple command-line calculator
Usage:
user@users-compputer:~$ cd expression
user@users-computer:~/expression$ make
user@users-computer:~/expression$ ./expression
::: (((5-2) * 3) + 3) / 4
: 3.000000
::: 7 - (-3)
: 10.000000
::: 6 - -4
: 10.000000
::: exit
Exiting...
user@users-computer:~/expression$