How to convert hex to string?

[Rostfrei]

Hello! I have some char array of hexadecimal values I get from the network. I want to convert them to some printable form. For example I did it like: string print_buff; char buffer2[100] = {0x7f, 0x80, 0x1a}; for(int i = 0; i < 3; i++){ char a[3] = {0}; sprintf(a, "%2.0x", buffer2[i]); print_buff.append(a, 2); } This works well to the values 0x7f (127), but for the numbers bigger than 0x7f it doesn't work properly anymore. If I look at 'a[3]' character array (in debuger) I can see that 0x80 has converted to "ffffff80" string. How is this even possible when I limited string with formating option to 2? When I append characters afterwards, "ff" is appended not "80". Rostfrei

[Owner drawn]

Rostfrei wrote:

char a[3] = {0};

You have to increase the size of the array(may be something like a[10], this will be much safer).

Jesus Lives Forever - Amen:rose:

--Owner drawn:rose: --An eye for an eye makes the whole world blind. --Jesus is Lord:rose:

[Rostfrei]

I tried that already, but it doesn't work. Rostfrei

[Owner drawn]

7f ff 1a. I am getting this as output.

Jesus Lives Forever - Amen:rose:

--Owner drawn:rose: --An eye for an eye makes the whole world blind. --Jesus is Lord:rose:

[Rostfrei]

Yes and it should be 7f 80 1a Rostfrei

[Owner drawn]

Rostfrei wrote:

char buffer2[100] = {0x7f, 0x80, 0x1a};

Here is the problem. Make that unsigned char buffer2[100];

Jesus Lives Forever - Amen:rose:

--Owner drawn:rose: --An eye for an eye makes the whole world blind. --Jesus is Lord:rose:

[Rostfrei]

Yes! It works now! Thank you! Rostfrei

[Stephen Hewitt]

In my oppinion there is way too much printfing in C++ code. Why not something like this? #include <sstream> #include <iomanip>   string print_buff; BYTE buffer2[100] = {0x7f, 0x80, 0x1a};   for(int i = 0; i < 3; i++) {      ostringstream ss;      ss << setw(2) << setfill('0') << hex << buffer2[i];      print_buff += ss.str(); } Steve

[Owner drawn]

Game over ;P :jig:

Jesus Lives Forever - Amen:rose:

--Owner drawn:rose: --An eye for an eye makes the whole world blind. --Jesus is Lord:rose:

[Gary R Wheeler]

In most C++ compilers, char is a signed data type. This means that values greater than or equal to 0x80 interpret the high bit as a sign bit. You are using an integer format %2.0x, so it extends the sign bit. Try this:

string print_buff;

char buffer2[100] = {0x7f, 0x80, 0x1a};

for(int i = 0; i < 3; i++){
char a[3] = {0};
sprintf(a, "%02x", **(unsigned)**buffer2[i]);
print_buff.append(a, 2);
}

The (unsigned) cast converts the character to an unsigned int. I also changed the format slightly.

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[Rostfrei]

Hello! By looking at the code I know it should work, but it just doesn't and I don't know why. I have an array of hexadecimal numbers (char) 00 1C 61 1A 80 02 07 80 A1 08 06 06 2B 0C 00 81 34 01 A2 03 02 01 00 A3 05 A1 03 02 01 01 when I try to convert it to string the result in print_buff is only "0". Rostfrei