if(isdigit(*argv[index])){...}
argv
is char **
, so *argv[index]
is just char
type, which can be converted to int
implicitly.
But argv[index]
is char *
type, to convert to int
, you need to convert explicitly.
solved Difference between *argv[index] (char**) and argv[index] (char*) passed to isdigit(int) [closed]