parity.c

parity.c

#include <stdio.h>
#include <stdlib.h>

void print_bits(int i) {
  printf("\n   ");
  int n = sizeof(int) * 8;
  for (int j = n-1; j >= 0; j--) {
    if (!((j+1) % 8)) {
      printf(" ");
    }
    char p = (i & (1 << j)) >> j;
    printf("%d", p);
  }
  printf("\n\n");
}

char parity(int i) {
  char p = 0;
  int n = sizeof(int) * 8;
  for (int j = 0; j < n; j++) {
    p += (i & (1 << j)) >> j;
  }
  return p % 2;
}

void usage(char *name) {
  printf("Usage: %s INT\n", name);
}

int main(int argc, char* argv[]) {
  if (argc < 2) {
    usage(argv[0]);
    return 1;
  }
  int i = atoi(argv[1]);
  print_bits(i);
  printf("Parity of %d is %d.\n", i, parity(i));
  return 0;
}