#include <stdio.h>
#include <errno.h>
#include <assert.h>
#include <stdlib.h>

void printfile(char *file);
void invalidArgs();

int main(int argc, char *argv[])
{
	if (argc==1)
	{
		invalidArgs();
	}
	int i;
	int keys=0;
	for (int i = 1; i < argc; ++i)
	{
		if (argv[i][0]!='-') { printfile(argv[i]); }
		else keys++;
	}
	if (keys==argc-1)
	{
		invalidArgs();
	}
	exit(0);
	return 0;
}

void printfile(char *file){
	assert(file!=NULL);
	FILE *fp = fopen(file, "rb");
	if (!fp)
	{
		fprintf(stderr, "Can't open input file %s!\n", file);
		exit(ENOENT);
	}
	int buff;
	while ((buff=fgetc(fp)) != EOF){
        printf("%c", buff);
    }
	fclose(fp);
}

void invalidArgs(){
	fprintf(stderr, "usage: printfiles file1 [file2 ...]\n    file1, file2, etc.: files to print\n");
	exit(EINVAL);
}