How to count a line

line_count.c

#define BIT_LEN 7

float line_value(int line) {
  int i;
  int value = 0, count = 0;
  for(i=0; i < BIT_LEN; ++i) {
    int mask = (1 << (i));
    if((line & (mask)) == (mask)) {
      value += i:
      count++;
    }
  }
  return value/count - BIT_LEN/2;
}