Programming Forums > Application Development > C

JawaKing00 · Sep 7th, 2005, 10:53 AM

Ok, I've been working with embedded C for too long and am too accustomed to using hexidecimal by default.

I'm trying to write a small piece of code that will read a .hex file and compute a 16 bit checksum of the contents. The problem I'm having is that I can't seem to figure out how to get C to read the characters in the file as hex numbers and not ANSI characters.

Ultimately I want the program to grab a pair of characters (aka one byte) and then add all of them together and display the result as a hex number.

Basically how can I tell the program that "01" = 16, "FF" = 255, etc. ?

Thanks in advance for the help.

JawaKing00 · Sep 7th, 2005, 1:10 PM

Bah, I wrote ANSI, but I meant ASCII.

I want to change ASCII values to hex from a file.

To darn many acronyms.

jim mcnamara · Sep 7th, 2005, 1:57 PM

(Toggle Plain Text)

#include <stdlib.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
    FILE *in=fopen(argv[1],"r");
    char tmp[128]={0x0};
    int i=0;
    int sum=0;
    
    while(fscanf(in,"%2x",&i)!=EOF)
    {
        sum+=i;
    }
    printf("Sum of the file in hex %x or %d\n",sum,sum);
    fclose(in);
    return 0;    
}

output:

(Toggle Plain Text)

Sum of the file in hex 257 or 599

contents of file:

(Toggle Plain Text)

 
b0
de
0a
a0
1f

JawaKing00 · Sep 7th, 2005, 3:06 PM

cool, thanks for the help.

InfoGeek · Sep 9th, 2005, 5:07 AM

Quote:

Originally Posted by JawaKing00

Basically how can I tell the program that "01" = 16, "FF" = 255, etc. ?

BTW 0x01 != 16.
0x10==16

Sep 7th, 2005, 10:53 AM	#1
JawaKing00 Newbie Join Date: Sep 2004 Posts: 29 Rep Power: 0	Converting ANSI characters to hex for Checksum. Ok, I've been working with embedded C for too long and am too accustomed to using hexidecimal by default. I'm trying to write a small piece of code that will read a .hex file and compute a 16 bit checksum of the contents. The problem I'm having is that I can't seem to figure out how to get C to read the characters in the file as hex numbers and not ANSI characters. Ultimately I want the program to grab a pair of characters (aka one byte) and then add all of them together and display the result as a hex number. Basically how can I tell the program that "01" = 16, "FF" = 255, etc. ? Thanks in advance for the help.

Sep 7th, 2005, 1:57 PM	#3
jim mcnamara Hobbyist Programmer Join Date: Jun 2005 Location: New Mexico Posts: 228 Rep Power: 4	(Toggle Plain Text) #include <stdlib.h> #include <stdio.h> int main(int argc, char argv[]) { FILE in=fopen(argv[1],"r"); char tmp[128]={0x0}; int i=0; int sum=0; while(fscanf(in,"%2x",&i)!=EOF) { sum+=i; } printf("Sum of the file in hex %x or %d\n",sum,sum); fclose(in); return 0; } #include <stdlib.h> #include <stdio.h> int main(int argc, char argv[]) { FILE in=fopen(argv[1],"r"); char tmp[128]={0x0}; int i=0; int sum=0; while(fscanf(in,"%2x",&i)!=EOF) { sum+=i; } printf("Sum of the file in hex %x or %d\n",sum,sum); fclose(in); return 0; } output: (Toggle Plain Text) Sum of the file in hex 257 or 599 Sum of the file in hex 257 or 599 contents of file: (Toggle Plain Text) b0 de 0a a0 1f b0 de 0a a0 1f

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Sep 7th, 2005, 1:10 PM	#2
JawaKing00 Newbie Join Date: Sep 2004 Posts: 29 Rep Power: 0	Bah, I wrote ANSI, but I meant ASCII. I want to change ASCII values to hex from a file. To darn many acronyms.

Sep 7th, 2005, 3:06 PM	#4
JawaKing00 Newbie Join Date: Sep 2004 Posts: 29 Rep Power: 0	cool, thanks for the help.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Programming Forums > Application Development > C

Converting ANSI characters to hex for Checksum.