PROGRAM series
*     add the first 100 terms of a simple series
      IMPLICIT NONE
      REAL*8 sum
      INTEGER n
*     True BASIC automatically initializes variables to zero,
*     but other languages might not.
      sum = 0
      DO n = 1, 100
         sum = sum + 1.0D0/n/n
         WRITE(*,'(I6,F13.6)') n, sum
      END DO
      END