I'm trying to get the number out of the argv[1] string.
line of code I'm using:Code:argv[1] = -w50
if I check the return value of the sscanf() it is 0, indicated no numbers were found. Does the presence of the '-' mess sscanf() up?Code:sscanf(argv[1], "%d", &columnWidth);
More the presence of the w (-50 would just be, well, -50). There are libraries out there specifically for dealing with command-line options, if that's feasible for you; if you do want to roll your own, you have to remember that there is an actual option there (presumably the w means something and as such must be processed), and then you can worry about what's after the letter.
Yes, the '-w' is essential. What command would you recommend to extract the number from the string?
If you are parsing w (for instance), which you know is a single letter command that must be followed immediately by a number, then your number is at argv[1]+2, which would therefore be your first argument to sscanf. (Note well, though: if you allow them to type "-w 50" as well as "-w50", then argv[1]+2 would be a '\0' character, and the number would be in argv[2].)
Thanks! Got it working
If you want to expand on this with a library, I would take a look at popt. There's also getopt, but popt is easier to use in my opinion. For your example it would let you specify that -w is a paramter that accepts an argument and you can even do things like specify help text to go with it or to allow alternate spellings such as
Code:mycommand -w50 mycommand -w 50 mycommand --width=50
