условие: с файла по-байтно считываются символы (while (от первого до последнего символа))

   FILE *fp;
unsigned  char ch;
 
 
while(fread (&ch,1,1,fp))
{
 
printf("%c",ch);
 
}

unsigned char a[5];
fread(a, 1, 5, fp);

void main()
{
unsigned char f1[8];
FILE *fp;
unsigned  char ch;
unsigned char a[5];
unsigned char b;
 
 
printf("Ishodnii fail dla pereda4i \n");
gets(f1);
 
if((fp=fopen(f1, "rb")) == NULL)
   {
      printf("Oshibka otkritia \n");
      exit(1);
   }
 
while(fread (&a,1,5,fp))
{
b=Crc8(a,5);
printf("%s",a);
printf("\n");
printf("%c",b);
printf("\n");
}
printf("done");
fclose(fp);
}

while (fread(a, 1, 5, fp))

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
 
#define BLOCK_SIZE 5
#define FILE_NAME  argv[1]
 
/* calc of CRC-8 */
int crc8(unsigned char *data, size_t len) {
    unsigned char crc = 0xFF;
    unsigned int i = 0;
 
    while (len--) {
        crc ^= *data++;
        for (i = 0; i < 8; i++)
            crc = crc & 0x80 ? (crc << 1) ^ 0x31 : crc << 1;
    }
 
    return crc;
}
 
int main(int argc, char **argv) {
    unsigned char i = 0, crc = 0;
    unsigned char block[BLOCK_SIZE] = { 0 };
    FILE *pfile = NULL;
 
    if ((pfile = fopen(FILE_NAME, "rb")) == NULL) {
        fprintf(stderr, "can't open file \"%s\"", FILE_NAME);
        return EXIT_FAILURE;
    }
 
    printf("%24s | %s\n", "block", "crc");
    while (fread(block, sizeof(unsigned char), BLOCK_SIZE, pfile)) {
        crc = crc8(block, BLOCK_SIZE);
 
        for (i = 0; i < BLOCK_SIZE; ++i)
            printf("0x%.2x ", block[i]);
 
        printf("| 0x%.2x\n", crc);
 
        memset(block, 0, BLOCK_SIZE * sizeof(unsigned char));
    }
 
    if (!feof(pfile) || ferror(pfile)) {
        printf("Error of reading file\n");
        fclose(pfile);
        return EXIT_FAILURE;
    }
    
    fclose(pfile);
    printf("Done\n");
    return EXIT_SUCCESS;
}