how can I create a bitmaped data in c?

Question

I am trying to create a bitmaped data in , here is the code I used but I am not able to figure the right logic. Here's my code

bool a=1;
bool b=0;
bool c=1;
bool d=0;

uint8_t output = a|b|c|d;

printf("outupt = %X", output);

I want my output to be "1010" which is equivalent to hex "0x0A". How do I do it ??

Answer 1

The bitwise or operator ors the bits in each position. The result of a|b|c|d will be 1 because you're bitwise oring 0 and 1 in the least significant position.

You can shift (<<) the bits to the correct positions like this:

uint8_t output = a << 3 | b << 2 | c << 1 | d;

This will result in

    00001000 (a << 3)
    00000000 (b << 2)
    00000010 (c << 1)
  | 00000000 (d; d << 0)
    --------
    00001010 (output)

Strictly speaking, the calculation happens with ints and the intermediate results have more leading zeroes, but in this case we do not need to care about that.