Brado!

#include <stdio.h>
#include <ctype.h>

char* printuplow(char* word, char* input){
	
	if(input[0] == '\0'){
		return;
	}
	
	input[0] = toupper(input[0]);
	fprintf(stdout, "%s\n", word);
	printuplow(word, &input[1]);
	input[0] = tolower(input[0]);
	fprintf(stdout, "%s\n", word);
	printuplow(word, &input[1]);
}

int main(int argc, char** argv)
{
	if(argc>1)
	{
	fprintf(stderr, "%s\n", argv[1]);
	printuplow(argv[1], &argv[1][0]);
	}
	return 0;
}