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### 8.215 `POPCNT` — Number of bits set

Description:
  `POPCNT(I)` returns the number of bits set ('1' bits) in the binary representation of `I`.
Standard:
  Fortran 2008 and later
Class:
  Elemental function
Syntax:
  `RESULT = POPCNT(I)`
Arguments:

  I | Shall be of type `INTEGER`.

Return value:
  The return value is of type `INTEGER` and of the default integer kind.
Example:

                program test_population
                  print *, popcnt(127),       poppar(127)
                  print *, popcnt(huge(0_4)), poppar(huge(0_4))
                  print *, popcnt(huge(0_8)), poppar(huge(0_8))
                end program test_population

See also:
  POPPAR, LEADZ, TRAILZ