POPCNT — Number of bits set

POPCNT(I)

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

Parameters:

I – Shall be of type INTEGER.

Returns:

The return value is of type INTEGER and of the default integer kind.

Standard:

Fortran 2008 and later

Class:

Elemental function

Syntax:

RESULT = POPCNT(I)

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 — 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