How to handle C command line argument flags in a neater way?

I have this little piece of C code, which takes a set of command-line arguments --help, -h, -d and -o (each correspondingly representing "Help", "Hexadecimal", "Decimal", "Octal"), and I am calling certain functions depending in which argument is passed, -h will call hexaFlag(), -dh will call hexaFlag() and decFlag(). However, in order to do this, I am employing a block of if else that is messy. Is there any less convoluted way to achieve this? I was told to use a switch statement, but I do not know how I could use it here considering I am checking for different conditions each time.

main() function of the code I am referring to:

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

        if(argc == 1){
                printf("%s",usage());
                printf("Use --help for more options.\n");
        }
        else if(strcmp(argv[1], "--help") == 0){
                printf("%s", usage());
                printf("Options are:\n  -h = Hexadecimal values\n  -d = Decimal values\n  -o = Octal values\n  --help = Shows this message\n");
        }
        else if(strchr(argv[1], '-') != NULL){
                if(strchr(argv[1], 'h') != NULL){
                        hexaFlag(argc, argv);
                }
                if(strchr(argv[1], 'd') != NULL){
                        decFlag(2, argc, argv);
                }
                if(strchr(argv[1], 'o') != NULL){
                        octaFlag(argc, argv);
                }
        }
        else {
                decFlag(1, argc, argv);
        }
        return 0;
}