9.206 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.
See also:
POPPAR, LEADZ, TRAILZ
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

© Free Software Foundation
Licensed under the GNU Free Documentation License, Version 1.3.
https://gcc.gnu.org/onlinedocs/gcc-5.4.0/gfortran/POPCNT.html