PROGRAM C1401A
C THIS PROGRAM PICKS UP THE FIRST OCCURRENCE
C OF A NUMBER IN A LIST.
C A SENTINEL IS USED, AND THE ARRAY IS 1 MORE
C THAN THE MAX SIZE OF THE LIST.
      DIMENSION A(101)
      INTEGER A,MARK
      INTEGER END,I
      OPEN(UNIT=1,FILE='C1401.TXT')
      READ (UNIT=1,FMT=*) END
      READ(UNIT=1,FMT=*) (A(I),I=1,END)
      PRINT*,'INPUT NUMBER TO SEARCH FOR'
      READ (UNIT=*,FMT=*) MARK
      I=1
      A(END+1)=MARK
100   IF(MARK.NE.A(I))THEN
        I=I+1
        GOTO 100
      ENDIF
      IF(I.EQ.(END+1)) THEN
        PRINT*,' ITEM NOT IN LIST'
      ELSE
        PRINT*,' ITEM IS AT POSITION ',I
      ENDIF
      END