exit-status

Command line16

Objective

Write a program that prints the sum of its integer arguments on standard output and reports every failure through its exit status, not through a message on standard output.

examples

$ ./exit_status 3 7 2 | cat -e

12$

$ ./exit_status -4 10 -6

$ ./exit_status -2147483648; echo "status $?"

-2147483648 status 0

$ ./exit_status 2>/dev/null; echo "status $?"

status 1

$ ./exit_status 7 segfault 2>/dev/null; echo "status $?"

status 2

$ ./exit_status 2147483647 1 2>/dev/null; echo "status $?"

status 3

Constraints

Expected files

exit_status.c

Allowed functions

write

Allowed headers

<unistd.h>declares write

<limits.h>defines INT_MAX and INT_MIN

Tests

Run the tests to grade your code

Build

01One valid argument

02Three values are summed

03A negative value lowers the sum

04The sum itself can be negative

05A leading plus sign is accepted

06Zero as the only argument

07Leading zeros are still digits

08INT_MAX fits

09INT_MIN fits

10INT_MAX written with a plus sign

11The running sum may touch both bounds

12Twenty valid arguments

13No argument returns 1

14Letters return 2

15An empty argument returns 2

16A lone minus sign returns 2

17A lone plus sign returns 2

18A leftover character returns 2

19A leading space returns 2

20A trailing space returns 2

21Two signs return 2

22A decimal point returns 2

23The first bad argument decides the status

24A sum above INT_MAX returns 3

25A sum below INT_MIN returns 3

26The overflow counts even if the total would fit

27A value one past INT_MAX returns 3

28A value one past INT_MIN returns 3

29Twenty digits return 3 without wrapping