!-----  Ex6_1: Sorting Array Elements   -----
   PROGRAM Ex6_1_Sorting
      INTEGER :: m, mark(100), n = 0, max, maxi, i, j
      DO WHILE( n <= 99 )
          PRINT*, "Input integer, or negative one to stop:"
          READ*, m ;   IF( m <= 0 ) EXIT
          n = n + 1;    mark(n) = m
      END DO
!-----   Sorting
      DO i = 1, n-1
         max = mark(i)
         maxi = i
         DO j = i+1, n
            IF( mark(j) > max ) THEN
               max = mark(j)
               maxi = j
            END IF
         END DO
         IF( maxi /= i ) THEN
             mark(maxi) = mark(i)
             mark(i) = max
         END IF         
      END DO
!-----   Output
      DO i = 1, n
         PRINT "( ' Rank', I3, ' =', I10 )", i, mark(i)
      END DO
   END PROGRAM Ex6_1_Sorting