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

Basically is a bucket sort optimized:

• reserve a bit array of length n bits.
• clear the bit array (first for in main).
• read the items one by one (they must all be distinct).
  • set the i'th bit in the bit array if the read number is i.
• iterate the bit array.
  • if the bit is set then print the position.

Or in other words (for N < 10 and to sort 3 numbers 4, 6, 2) 0

start with an empty 10 bit array (aka one integer usually)

0000000000

read 4 and set the bit in the array..

0000100000

read 6 and set the bit in the array

0000101000

read 2 and set the bit in the array

0010101000

iterate the array and print every position in which the bits are set to one.

2, 4, 6

sorted.