How do I get bit-by-bit data from an integer value in C?

Question

I want to extract bits of a decimal number.

For example, 7 is binary 0111, and I want to get 0 1 1 1 all bits stored in bool. How can I do so?

OK, a loop is

Answer 1

If you don't want any loops, you'll have to write it out:

#include 
#include 

int main(void)
{
    int num = 7;

    #if 0
        bool arr[4] = { (num&1) ?true: false, (num&2) ?true: false, (num&4) ?true: false, (num&8) ?true: false };
    #else
        #define BTB(v,i) ((v) & (1u << (i))) ? true : false
        bool arr[4] = { BTB(num,0), BTB(num,1), BTB(num,2), BTB(num,3)};
        #undef BTB
    #endif

    printf("%d %d %d %d\n", arr[3], arr[2], arr[1], arr[0]);

    return 0;
}

As demonstrated here, this also works in an initializer.