Question

if for instance i have a string: Hi:my:name:is:lacrosse1991: how could I use strtok to retrieve just the is (in other words the fourth field)? This would be similar to how you would use cut in bash, where i would just do cut -d ":" -f 4. If this is the wrong function to be doing such a thing, please let me know, any help is much appreciated, thanks! (I’ve just recently started teaching myself C, I apologize ahead of time if these are obvious questions that i am asking)

here is an example of the cut command that I would use

x=$(echo "$death" | cut -d ':' -f 4)
y=$(echo "$death" | cut -d ':' -f 5)
z=$(echo "$death" | cut -d ':' -f 6)

Answer 1

I’d avoid strtok for this purpose (and most others, for that matter). Under the circumstances, I think I’d just use sscanf with a scanset conversion:

char field_four[128];   
sscanf(input_string, "%*[^:]:%*[^:]:%*[^:]:%127[^:]:", field_four);

In this, we start by repeating %*[^:]: three times. Each of these reads a string including any characters except a colon, then a colon. The * means that should be read from the input, but ignored (not assigned to anything). Then, for the fourth field we have the same thing, except we do not include the *, so that field does get assigned, in this case to field_four (though you should obviously use a more meaningful name).

For the fourth field, I’ve also added a specification of the maximum length. Since sscanf always includes a \0 to terminate the string, but doesn’t include it in the count, we need to specify a size one smaller than the size of the buffer.