Converting unsigned short int to its hex representation

[yeah1000]

Hello, i ran into a bit of trouble when converting unsigned short int to its hex string representation. What i need is a two byte representation with a space between the bytes (e.g "0f 43" for 3907 of "00 ff" for 255) The solution i came up with is the following: unsigned char* CreateHexValues(unsigned short int inValue) { char Hex[5] = {0, 0, 0, 0, 0}; _itoa_s(inValue, Hex, 16); unsigned char *hexOut = new unsigned char[5]; hexOut[2] = ' '; if(inValue <= 15) { hexOut[0] = '0'; hexOut[1] = '0'; hexOut[3] = '0'; hexOut[4] = Hex[0]; } else if(inValue > 15 && inValue <= 255) { hexOut[0] = '0'; hexOut[1] = '0'; hexOut[3] = Hex[0]; hexOut[4] = Hex[1]; } else if(inValue > 255 && inValue <= 4095) { hexOut[0] = '0'; hexOut[1] = Hex[0]; hexOut[3] = Hex[1]; hexOut[4] = Hex[2]; } else if (inValue > 4096) { hexOut[0] = Hex[0]; hexOut[1] = Hex[1]; hexOut[3] = Hex[2]; hexOut[4] = Hex[3]; } return hexOut; } So my question is: is there a better/quicker way to do that? The problem is that when i convert it with _itoa_s it could be in the following formats: f43, 43, 3 (depending on inValue) without any zeros in front of it. Another problem is with the Hex[5] array, my inValue can never be bigger than 65535, but for some reason i get an assertion failure when i change its size to Hex[4] which should be enough for 65535. Why could that be? Thanks for all replies in advance

[Lost User]

A simpler way is to use the one of the xprintf() type functions. Take a look here[^] at the x and X format specifiers.

[CPallini]

I would do

void CreateHexValues(unsigned short inValue, char hexOut[6])
{
sprintf(hexOut, "%02x %02x", (inValue >> 8), (inValue & 0xFF) );
}

:) Please note: Array allocation is, by design...:rolleyes:, responsibility of the caller.

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles]

modified on Tuesday, November 3, 2009 9:27 AM

[David Crow]

CPallini wrote:

void CreateHexValues(unsigned short inValue, char hexOut[5])

Shouldn't it be hexOut[6] to make room for the \0 character?

"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown

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[CPallini]

Definitely! :-O Fixed: thank you! :) BTW: Shhhhhhhhhhhhhhhhhhhhh, don't tell Rajesh! :rolleyes:

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles]

[yeah1000]

Thank you very much, brilliant solution ;)

[softwaremonkey]

How about something like:

char szBuffer[10];
short value = 1234;
sprintf(szBuffer, "%02X %02X", HIBYTE(value), LOBYTE(value));

Tony