[Dev-C++] Anomaly for new user

[Jerome K. <jj...@ya...>]

/*Hi Everybody-
Im new, wrote this little program to see how I could pack some
bcd bytes for another project. Im curious why I get "ffffff8 _ when I enter 8
or 9 for the first or 3rd digit. Can some one explain where this comes
from? I can get rid of it with 

     printf ("packed value of digits is %2X \n", (digit[i]& 0x0ff));

but Im curious where it comes from and why only for 8 or 9, must have to do with bit 3.

Thanx
Mot
*/
//==================================================
#include <stdio.h>
#include <stdlib.h>
#include <conio.h>

int i,j =0;
char digit[5];

//this program takes in 4 digits from the keyboard and packs them into 2 packed-bcd bytes.

int main(int argc, char *argv[])
{

     for (i=0;i<4; i++) {// 4 single digits = two packed bcd bytes
      while (!kbhit()); //wait
      digit[i]=getch(); // getch gets the char from the buffer 
      printf("%d",digit[i],"\n"); // echo back
      printf("   ascii the value of i is %d\n",i);
     }    
 
 //now convert from ascii to hex
 for (i=0;i<4; i++) {// 4 single digits = two packed bcd bytes
  digit[i]=digit[i]-48; //convert from ascii to decimal
  printf("%d",digit[i],"\n"); // echo back
  printf("   the value of i is %d\n\n",i);
  }
 
 //now pack the bcd
  digit[0]= (digit[0]<<4) | (digit[1]);
  digit[1]= (digit[2]<<4) | (digit[3]);
  printf ("digits packed are   %x     %x  \n\n", digit[0],digit[1]);
  
  system("PAUSE");    
  return 0;
}
//==========================================================