for (i=1; i<argc && argv[i][0] == '-'; i++) {
if (strspn(argv[i]+1, "qRu")+1 != strlen(argv[i])) {
fprintf(stderr, "Unknown flag <%s>\n", argv[i]);
for (i=1; i<argc && argv[i][0] == '-'; i++) {
if (strspn(argv[i]+1, "qRu")+1 != strlen(argv[i])) {
fprintf(stderr, "Unknown flag <%s>\n", argv[i]);