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8.222 POPCNT — Number of bits set ¶

Synopsis:

RESULT = POPCNT(I)

Description:

POPCNT(I) returns the number of bits set (’1’ bits) in the binary representation of I.

Class:

Elemental function

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

Standard:

Fortran 2008 and later

See also:

POPPAR — Parity of the number of bits set,
LEADZ — Number of leading zero bits of an integer,
TRAILZ — Number of trailing zero bits of an integer