I have the following C code fragment and have to identify the error and suggest a way of writing it more safely:
char somestring[] = "Send money!\n";
char *copy;
copy = (char *) malloc(strlen(somestring));
strcpy(copy, somestring);
printf(copy);
So the error is that strlen ignores the trailing '\0'
of a string and therefore it is not going to be allocated enough memory for the copy but I'm not sure what they're getting at about writing it more safely?
I could just use malloc(strlen(somestring)+1))
I assume but I'm thinking there must be a better way than that?
EDIT: OK, I've accepted an answer, I suspect that the strdup solution would not be expected from us as it's not part of ANSI C. It seems to be quite a subjective question so I'm not sure if what I've accepted is actually the best. Thanks anyway for all the answers.
char somestring[] = "Send money!\n";
char *copy;
size_t copysize;
copysize = strlen(somestring)+1;
copy = (char *) malloc(copysize);
if (copy == NULL)
bail("Oh noes!\n");
strncpy(copy, somestring, copysize);
printf("%s", copy);
Noted differences above:
malloc()
must be checked!strncpy()
because strcpy()
is naughty. In this contrived example it won't hurt, but don't get into the habit of using it.EDIT:
To those thinking I should be using strdup()
... that only works if you take the very narrowest view of the question. That's not only silly, it's overlooking an even better answer:
char somestring[] = "Send money!\n";
char *copy = somestring;
printf(copy);
If you're going to be obtuse, at least be good at it.