subroutine hash13(n13,c13,isave) parameter (NMAX=20) character*13 c13,callsign(NMAX) integer ihash(NMAX) logical first data first/.true./ save first,ihash,callsign if(first) then ihash=-1 callsign=' ' first=.false. endif if(isave.ge.0) then do i=1,NMAX if(ihash(i).eq.n13) go to 900 !This one is already in the list enddo ihash(NMAX:2:-1)=ihash(NMAX-1:1:-1) callsign(NMAX:2:-1)=callsign(NMAX-1:1:-1) ihash(1)=n13 callsign(1)=c13 else do i=1,NMAX if(ihash(i).eq.n13) then c13=callsign(i) go to 900 endif enddo endif 900 return end subroutine hash13