The program works like this, argument is supplied in a form like this at the beginning:
-w cat
The string "cat" is stored in variable pattern and for each letter that is followed by - we do something; in this case we set mode = W. What I have trouble with is when the argument is in the form:
-w -s -n3,4 cat
Now I believe that as before mode is set to W,S and N in the order that is read. And If I wanted to store/remember what order sequence of letters mode was set to after the loop is done, I can store the information in an array. Also as should be done pattern is assigned the string "cat". Correct me if I am wrong or is there an easier way to do this.
Secondly, I want to be able to access and store the numbers 3 and 4. I am not sure how that is done and I am not sure what argc -= optind; and argv += optind; does. Except that I think the arguments are stored in a string array.
enum MODE { W,S,N } mode = W; int c; while ((c = getopt(argc, argv, ":wsn")) != -1) { switch (c) { case 'w': mode = W; break; case 's': mode = S; break; case 'n': mode = N; break; } } argc -= optind; argv += optind; string pattern = argv[0]; Update: figured out how to access the numbers, I just had to see what was in argv during the loop. So I guess I will just store the value I find there in another variable to use.
31 Answer
getopt sets the global variable optarg when a parameter with a value has been provided. For example:
for(;;) { switch(getopt(argc, argv, "ab:h")) // note the colon (:) to indicate that 'b' has a parameter and is not a switch { case 'a': printf("switch 'a' specified\n"); continue; case 'b': printf("parameter 'b' specified with the value %s\n", optarg); continue; case '?': case 'h': default : printf("Help/Usage Example\n"); break; case -1: break; } break; } See here for a more complete example.
I want to be able to access and store the numbers 3 and 4.
Since this is a comma delimited list you will need to parse optarg for the tokens (see strtok) and then use atoi or similar to convert each one to an integer.
