CODEWITHSUNDEEP
cprintf
stelios
stelios

Reputation: 1027

Copy hex values with sprintf in C

From the code below I am trying to get the result of the result var into a string var but no success so far. What's wrong? Why I can't get the right result? If I print this directly it's ok...

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/md5.h>

char *string = "stelios";
unsigned char s[MD5_DIGEST_LENGTH];
int main()
{
 int i;
 unsigned char result[MD5_DIGEST_LENGTH];

  MD5(string, strlen(string), result);

  // output
  for(i = 0; i < MD5_DIGEST_LENGTH; i++){
   sprintf(s,"%0x", result[i]);//
   printf("%x",s[i]);
  }
   printf("\n%x",s);

   return EXIT_SUCCESS;
  }

Upvotes: 0

Views: 7272

Answers (3)

lhf
lhf

Reputation: 72312

Here's what I've used:

  char *digit="0123456789abcdef";
  char hex[2*MD5_DIGEST_LENGTH+1],*h;
  int i;
  for (h=hex,i=0; i<N; i++)
  {
   *h++=digit[digest[i] >> 4];
   *h++=digit[digest[i] & 0x0F];
  }
  *h='\0';

Upvotes: 0

jwodder
jwodder

Reputation: 57460

Each time sprintf is called, it writes the formatted value to the beginning of s, overwriting whatever was written there in the previous call. You need to do something like sprintf(s + i*2, "%02x", result[i]); (and change the length of s to 2*MD5_DIGEST_LENGTH+1).

Upvotes: 2

Mohamed Nuur
Mohamed Nuur

Reputation: 5645

Try this:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/md5.h>

char *string = "stelios";
char s[MD5_DIGEST_LENGTH * 2 + 1] = "";
int main()
{
  int i;
  unsigned char result[MD5_DIGEST_LENGTH];

  MD5(string, strlen(string), result);

  // output
  for(i = 0; i < MD5_DIGEST_LENGTH; i++){
    char temp[3];
    sprintf(temp, "%02x", result[i]);
    strcat(s, temp);
  }
  printf("Final Hex String: %s",s);

  return EXIT_SUCCESS;
}

Upvotes: 2

Related Questions