PROGRAM GRADE
      PARAMETER (N=7)
      IMPLICIT DOUBLE PRECISION (A-H,O-Z)
      DIMENSION P(N,2),G(N,2),PMX(1000)
      CHARACTER *2 LETTER(N)
      DATA (P(I,1),P(I,2),I=1,N)/75,100,65,75,55,65,45,55,35,45,
     *25,35,0,25/
      DATA (G(I,1),G(I,2),I=1,N)/5.5,6.0,4.5,5.5,3.5,4.5,2.5,3.5,
     *1.5,2.5,0.5,1.5,0.0,0.5/
      DATA (LETTER(I),I=1,N)/'O', 'A', 'B', 'C', 'D', 'E', 'F'/
      P(1,2)=P(1,2)+0.000001D0
      G(1,2)=G(1,2)+0.000001D0
      WRITE(*,*)'CONVERT % MARKS INTO GRADE POINTS? FEED 1'
      WRITE(*,*)'CONVERT GRADE POINTS INTO % MARKS? FEED 0'
      READ(*,*) NCGM
      WRITE(*,*)'NO. OF % MARKS/GRADE POINTS TO BE CONVERTED ?'
      READ(*,*) M

      WRITE(*,*)'FEED % MARKS OR GRADE POINTS (WHICHEVER APPLICABLE)'
      READ(*,*)(PMX(I),I=1,M)
      WRITE(*,*)'------------------------------------------------------'
      WRITE(*,*)'SL NO.     MARKS (%)      GRADE POINT     LETTER GRADE'
      WRITE(*,*)'------------------------------------------------------'
      IF(NCGM.EQ.1) THEN
      DO IX=1,M
      PM=PMX(IX)
      K=0
      DO I=1,N
      IF(P(I,1).LE.PM.AND.P(I,2).GT.PM) K=I
      ENDDO
      GP=G(K,1)+(PM-P(K,1))*(G(K,2)-G(K,1))/(P(K,2)-P(K,1))
      WRITE(*,1)IX, PM, GP, LETTER(K)
      ENDDO
      ELSE
      DO IX=1,M
      GP=PMX(IX)
      K=0
      DO I=1,N
      IF(G(I,1).LE.GP.AND.G(I,2).GT.GP) K=I
      ENDDO
      PM=P(K,1)+(GP-G(K,1))*(P(K,2)-P(K,1))/(G(K,2)-G(K,1))
      WRITE(*,1)IX, PM, GP, LETTER(K)
      ENDDO
      ENDIF
    1 FORMAT(1X,I3,9X,F7.3,8X,F7.3,12X,A3)
      WRITE(*,*)'------------------------------------------------------'
      WRITE(*,*)'OVER '
      READ(*,*) XX
      END