everest% cc parse.c token.c
parse.c:
token.c:
everest% 

everest% a.out
Enter an expression (<255 char): 3 + 4
Value = 7
everest% 

everest% a.out
Enter an expression (<255 char): 3 * 4
Value = 12
everest% 

everest% a.out
Enter an expression (<255 char): 3 * (2 + 4) 
Value = 18
everest% 

everest% a.out
Enter an expression (<255 char): 123 + 4 * 5
Value = 143
everest% 

everest% a.out
Enter an expression (<255 char): 123 + 40 * 5 - 7 * 11
Value = 246
everest% 

everest% a.out
Enter an expression (<255 char): 3 * 2 + 4
Value = 10
everest% 

everest% a.out
Enter an expression (<255 char): 3 - 1 - 1
Value = 1
everest% 

everest% a.out
Enter an expression (<255 char): 1 + (2 * (3 + (4 / 2)))
Value = 11
everest% 

everest% a.out
Enter an expression (<255 char): 3 4
3 4
  ^--- syntax error
Garbage at the end
everest% 

everest% a.out
Enter an expression (<255 char): 3 + (4 * 5
3 + (4 * 5
          ^--- syntax error
Expecting ')'
everest% 

everest% a.out
Enter an expression (<255 char): x - 1
x - 1
^--- syntax error
Expecting a number or '('
everest% 

everest% a.out
Enter an expression (<255 char): (3 + 7) / 2 - 11 * * 4
(3 + 7) / 2 - 11 * * 4
                   ^--- syntax error
Expecting a number or '('
everest%