Bits Concatenation C++

[Thuthu001]

Hi,
I need help with concatenating several bits values to one big value.
For example:
lets say I have these char variables which I want to concatenate to one value.
unsigned char x = 0x02; //00000010
unsigned char y = 0x01; //00000001
unsigned char z = 0x03; //00000011

and the output should be,e.g. 000000100000000100000011

Can someone please advice on how do I do this.

[stereoMatching]

std::bitset or boost::dynamic_bitset

[Bazzy]

you can use bit-wise operators http://www.cplusplus.com/doc/tutorial/operators/
( you'll need to promote characters to bigger types )

[sohguanh]

Bit-wise operators can be hard to debug and read when problem crept up. Thanks for stereoMatching post, now I know there is a std::bitset class I can use directly and this is a God given gift to C/C++ programmers again!!!

[rocketboy9000]

This problem is common when dealing with RGB colors as integers. Here is a x86 specific way that is much faster than bitwise operators:

int color;
char *pcolor=(char*)&color;
pcolor[0]=z;
pcolor[1]=y;
pcolor[2]=x;

And now color has the value you asked for.
And now everyone will murder my guts for teaching pointer casts.

[guestgulkan]

Personally I would have gone for the standard bitshift and bitwise or

[ne555]

@rocketboy9000

union RGBA{
	//int icolor; //sorry about the Hungarian
	long lcolor;
	char acolor[4];
};

However to work sizeof(int) must be greater or equal than 4.
Edit: Be careful with endianness.

What do you want to accomplish?
What operations do you need to perform that the data should be in that way?