C program for bit pattern search?

Question

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I above Ouput I Missed two stars.My question is how to find out the remaining stars.Please tel me in the C programming way.

Answer 1

check this small program, you need to pass the pattern_mask correctly say you want to check the pattern 110 then mask would be 111 i.e. 0x07. Rest is very simple.

int pattern_check(int number, int pattern, int pattern_mask) 
{
    int count = 0;
    while(number > 0) {

        if( !((number ^ pattern) & pattern_mask) ) {
            ++count;
        }

        number >>= 1;
    }

    return count;
}

int main(void)
{

    unsigned int number = 0xa2;
    unsigned int pattern = 0x02;
    unsigned int pattern_mask = 0x03;

    int count = pattern_check(number, pattern, pattern_mask);

    printf("\ncount:  %d\n", count);

    return 0;
}