#include <stdio.h>

/*  HEX standard input to standard output */
void HEX_digit(short di);

main(int argc, char *argv[])
{	short	c;
	short	hi, low;
	short	nl;
	FILE	*file;

if(argc!=2) {printf("Opps!\n");return;}
file=fopen(argv[1],"r");
if(file==0) {printf("File %s failed to open.\n",argv[1]);return;}
nl=0;
while ( (c=getc(file))!=EOF ) {
	hi=c/16;low=c-16*hi;
	HEX_digit(hi);HEX_digit(low);
	nl++;
	if(nl>15) { nl=0; putchar('\n');} else putchar(' ');
	}
putchar('\n');
fclose(file);
}

void HEX_digit(short di)
{
if(di>9) putchar('a'-10+di); else putchar('0'+di);
}