C programming check digit

bool print_date(Date *d, char **argv) {

        if (isdigit(*argv+1)) {
                return printf("is d");
        } else {
                return printf("is not d");
        }

}

The above function don't work. *argv+1 is the user input, is it a string or what types when passing in? anyone can help?

 int main(int argc, char *argv[])
 {

  Date d;

  get_date(&d, arg开发者_开发百科v);


 }

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*argv+1 computes the address to the first character of the 0-th argument (that is the executable name) and adds 1 to shift to second char of it.. I don't think this is what you want to do.

You could try by using argv[1], this will mean the first argument after the executable name, as a char *.

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I am guessing that what you really want is *(argv + 1). The way you have it written is that it will dereference the first character of the program, add one and then test if it is a digit.