#include <stdio.h>

int main(int argc, char *argv[])
{
	int character;
	unsigned int ccase = 0;
	int iter = 1;
	FILE *filep = stdin;
	if (argv[1] && argv[1][0]=='-' && argv[1][1]) {
		switch (argv[1][1]) {
			case 'l': ccase = 'l'; break;
			case 'u': ccase = 'u'; break;
			case 's': ccase = 's'; break;
		}
	}
	else {
		fprintf(stderr, "sc: usage: sc -[ l|u|s ] [file...]\n");
		return 1;
	}
	argc--;
	argv++;

	do {
		if (argc > 1 && (filep=fopen(argv[iter], "r"))==NULL) {
			fprintf(stderr, "sc: unable to open %s\n", argv[iter]);
			continue;
		}

		switch (ccase) {
		case 'l':
			while ((character = fgetc(filep))!=EOF) {
				if (character >= 'a' && character <= 'z')
			 		character += 32;
				putchar(character);
			}
		break;

		case 'u':
			while ((character = fgetc(filep))!=EOF) {
				if (character >= 'a' && character <= 'z')
			 		character -= 32;
				putchar(character);
			}
		break;

		case 's':
			while ((character = fgetc(filep))!=EOF) {
				if (character >= 'a' && character <= 'z') {
			 		character -= 32;
					putchar(character);
					continue;
				}
				else if (character >= 'a' && character <= 'z') {
			 		character += 32;
					putchar(character);
					continue;
				}
				putchar(character);
			}
		break;
		}
	} while (++iter<argc);
	return 0;
}