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You can do that using the following macros, which in turn use bit masking and shifting:<br />

<pre><code id="code-311996">#define LO(x) (x &amp; 0x0F) // extracts the lower four bits
#define HI(x) ((x &amp; 0xF0) &gt;&gt; 4) // extracts the upper four bits and shifts them down by 4 
int upper = HI(*code);
int lower = LO(*code);
</code></pre>
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You can do that using the following macros, which in turn use bit masking and shifting:


#define LO(x) (x & 0x0F) // extracts the lower four bits
#define HI(x) ((x & 0xF0) >> 4) // extracts the upper four bits and shifts them down by 4 
int upper = HI(*code);
int lower = LO(*code);


<div>
Hmm, I have no doubt that will work, but since I have not done any bitmasking before, could you explain how what you have there extracts the two parts? Also, if possible, could you show me a non-macroed solution?
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Hmm, I have no doubt that will work, but since I have not done any bitmasking before, could you explain how what you have there extracts the two parts? Also, if possible, could you show me a non-macroed solution?

<div>
Bang. There we go - awesome, thanks. 
</div>


<div>
If you use that solution (with a right-shift in it), then make sure to use an unsigned char, and not just a char. As a rule, when bit shifting is involved, always use unsigned integer types !!
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If you use that solution (with a right-shift in it), then make sure to use an unsigned char, and not just a char. As a rule, when bit shifting is involved, always use unsigned integer types !!

<div>
<div class="content wysiwyg-content">
Hi All,<br />
<br />
I'm reading in some data from a file like so:<br />
<br />
char * code = new char[1];<br />
infile.read(code, 1);<br />
<br />
Within this byte of data there are two numbers I need to extract - they are represented by the first 4 bits and the second four bits - how to go about splitting the byte up and extracting both numbers?<br />
<br />
Thanks<br />

</div>
</div>


Hi All,

I'm reading in some data from a file like so:

char * code = new char[1];
infile.read(code, 1);

Within this byte of data there are two numbers I need to extract - they are represented by the first 4 bits and the second four bits - how to go about splitting the byte up and extracting both numbers?

Thanks


Splitting up a bit into 2 x 4 bits

C++ is an intermediate-level general-purpose programming language, not to be confused with C or C#. It was developed as a set of extensions to the C programming language to improve type-safety and add support for automatic resource management, object-orientation, generic programming, and exception handling, among other features.