If you look at the declaration of main()
you see that it's
int main(int argc, const char **argv);
or
int main(int argc, const char *argv[]);
So argv
is an array of const char *
(i.e. character pointers or "C strings"). If you dereference argv[1]
you'll get:
"s"
or:
{ 's' , '\0' }
and if you dereference argv[1][0]
, you'll get:
's'
As a side note, there is no need to copy that character from argv[1]
, you could simply do:
const char *myarg = NULL;
int main(int argc, const char **argv) {
if (argc != 2) {
fprintf(stderr, "usage: myprog myarg\n");
return 1;
} else if (strlen(argv[1]) != 1) {
fprintf(stderr, "Invalid argument '%s'\n", argv[1]);
return 2;
}
myarg = argv[1];
// Use argument as myarg[0] from now on
}