CODEWITHSUNDEEP
c
Developers Staff
Developers Staff

Reputation: 71

How to convert a string to hex and vice versa in c?

How can i convert a string to hex and vice versa in c. For eg:, A string like "thank you" to hex format: 7468616e6b20796f75 And from hex 7468616e6b20796f75 to string: "thank you". Is there any ways to do this ?

Thanks in advance

Upvotes: 2

Views: 21774

Answers (3)

Mo Sa
Mo Sa

Reputation: 161

straight forward solution:

public static string ToHex(string str)
{
    byte[] bytes = Encoding.UTF8.GetBytes(str);
    return Convert.ToHexString(bytes);
}

to convert back to plain text:

public static string FromHex(string str)
  {
      byte[] bytes = new byte[str.Length / 2];
      for (int i = 0; i < bytes.Length; i++)
          bytes[i] = Convert.ToByte(str.Substring(i * 2, 2), 16);

      return Encoding.UTF8.GetString(bytes);
  }

caller:

string hex = ToHex("my name is moe");

returns: 6D79206E616D65206973206D6F65

string val = FromHex(hex);

Upvotes: 0

Gues
Gues

Reputation: 11

To convert a string to its hexadecimal code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int main( )
{
    int i;
    char word[] = "KLNCE";
    char hex[20];
    for ( i = 0; i < strlen ( word ); i++ )
    {
        char temp[5];
        sprintf( temp, "%X", word[i] );
        strcat( hex, temp );
    }
    printf( "\nhexcode: %s\n", hex );
    return 0
}

OUTPUT

hexcode: 4B4C4E4345

Upvotes: 1

Gene
Gene

Reputation: 47020

sprintf and sscanf are good enough for this.

#include <stdio.h>
#include <string.h>

int main(void) {
  char text[] = "thank you";
  int len = strlen(text);

  char hex[100], string[50];

  // Convert text to hex.
  for (int i = 0, j = 0; i < len; ++i, j += 2)
    sprintf(hex + j, "%02x", text[i] & 0xff);

  printf("'%s' in hex is %s.\n", text, hex);

  // Convert the hex back to a string.
  len = strlen(hex);
  for (int i = 0, j = 0; j < len; ++i, j += 2) {
    int val[1];
    sscanf(hex + j, "%2x", val);
    string[i] = val[0];
    string[i + 1] = '\0';
  }

  printf("%s as a string is '%s'.\n", hex, string);

  return 0;
}

Now

$ ./a.out
'thank you' in hex is 7468616e6b20796f75.
7468616e6b20796f75 as a string is 'thank you'.

Upvotes: 5

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