rock_1.c

#include <stdio.h>
#include <string.h>

void f1(const char *filename);

int main(int argc, const char *argv[])
{
	if(argc<2) return 0;

	f1(argv[1]);

	return 0;
}

void f1(const char *filename)
{
	char buffer[4096]; // Q_________Q

	size_t len = strlen(filename);
	size_t size = len > 4096 ? len : 4096;
	strncpy(buffer, filename, size);

	char *p = buffer;
	while(*p != '\0'){
		if(*p >= 'a' && *p <= 'z')
			*p -= 'a' - 'A';
		p++;
	}

	printf("%s", buffer);
}