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  1. #include <stdio.h>
  2.  
  3. char split_lookup[] = {
  4. 	0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4
  5. };
  6.  
  7. int bit_count(unsigned char n) {
  8. 	return split_lookup[n&0xF] + split_lookup[n>>4];
  9. }
  10.  
  11. int main(void) {
  12.  
  13. for (int i = 0 ; i != 256 ; i++) {
  14.     int count = 0;
  15.     for (int p = 0 ; p != 8 ; p++) {
  16.         if (i & (1 << p)) {
  17.             count++;
  18.         }
  19.     }
  20.     if (bit_count(i) != count) {
  21.         printf("Bad: %d\n", i);
  22.     }
  23. }
  24.  
  25.  
  26. 	return 0;
  27. }
  28.  
Success #stdin #stdout 0s 2004KB
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Standard input is empty
stdout
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Standard output is empty
https://ideone.com/xjS9Bz
language:
C99 (gcc 8.3)
created:
10 years ago
visibility:
public

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