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  <title>Evil — Kernighan</title>
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<body>
  <h1>Kernighan set-bit loop</h1>
  <p>Edit values in <code>tests</code>, then click <strong>Run</strong>.</p>
  <pre id="out"></pre>
  <script>
    (function () {
      function popcountKernighan(n) {
        var ones = 0;
        while (n) {
          n &= n - 1;
          ones += 1;
        }
        return ones;
      }
      function isEvilKernighan(n) {
        if (n < 0) {
          return false;
        }
        return popcountKernighan(n) % 2 === 0;
      }
      var tests = [15, 7, 0, 3];
      var lines = [];
      for (var i = 0; i < tests.length; i++) {
        var n = tests[i];
        var label = isEvilKernighan(n) ? "evil" : "odious";
        lines.push(n + ": " + label + " (ones=" + popcountKernighan(n) + ")");
      }
      document.getElementById("out").textContent = lines.join("\n");
    })();
  </script>
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