How do the bit manipulations in this bit-sorting code work?

Question

Jon Bentley in Column 1 of his book programming pearls introduces a technique for sorting a sequence of non-zero positive integers using bit vectors.

I have taken the p

Answer 1

Quoting the excerpts from Bentleys' original article in DDJ, this is what the code does at a high level:

/* phase 1: initialize set to empty */

for (i = 0; i < n; i++)

    bit[i] = 0

/* phase 2: insert present elements */

for each i in the input file

    bit[i] = 1

/* phase 3: write sorted output */

for (i = 0; i < n; i++)

    if bit[i] == 1

        write i on the output file