REAL KK, MUS
                    INTEGER ENDD
                    DIMENSION H0(15,6), H(15,6)
                    ENDD=0
                    NI=15
                    NJ=6
                    NI01=NI-1
                    NJ01=NJ-1
                    NI02=NI-2
                    NJ02=NJ-2
                    DX=100.0
                    KK=1.0
                    MUS=0.00001
                    DT=0.25  
                    LAMDA=KK*DT/(MUS*DX*DX)
                    DO 5 I=2,NI01
                    DO 5 J=2,NJ01
              5       H0(I,J)=0.0
                    DO 10 I=2,7
                    H0(I,1)=10.0
              10       H(I,1)=10.0
                    DO 12 I=9,NI01
              12    H(I,1)=0.0
                    MDT=0
                    TIME=0.
                    IPRINT=50
                    ICOUNT=0
              20    MDT=MDT+1
                    TIME=TIME+DT
                    DFMAX=0.0
                    ICOUNT=ICOUNT+1
                    DO 25 J=2,NJ01
                    H0(1,J)=H0(3,J)
              25       H0(NI,J)=H0(NI02,J)
                    DO 27 I=2,NJ01
              27    H0(I,NJ)=H0(I,NJ02)
                    DO 30 I=2,NI01
                    DO 30 J=2,NJ01
              30       H(I,J)=(H0(I-1,J)+H0(I+1,J)+H0(I,J-1)+H0(I,J+1))/4
                    H(8,1)=(H0(7,1)+H0(9,1)+2*H0(8,2))/4
                    IF (ICOUNT.NE.IPRINT) GO TO 40
                    OPEN(1,FILE=’DATA2.EXL’)
              35       WRITE(*,36) TIME
              36       FORMAT(/,5X,'TIME=',F11.6)
                    WRITE(*,37) ((H(I,J), I=2, NI01), J=1, NJ01)
              37       FORMAT(1X,'H(NI,NJ)=', / , (13F6.2,1X))
                    IF(ENDD.EQ.1) GO TO 100
                    ICOUNT=0
              40       DO 45 I=2, NI01
                    DO 45 J=1, NJ01
                    DF=ABS(H(I,J)-H0(I,J))
                    IF(DF.GT.DFMAX)DFMAX=DF
              45       CONTINUE
                    IF(DFMAX.LT.0.001)GOTO 80
                    DO 50 I=2,NI01
                    DO 50 J=2,NJ01
              50       H0(I,J)=H(I,J)
                    H0(8,1)=H(8,1)
                    GO TO 20
              80       ENDD=1
                    GO TO 35
             100    CONTINUE
                    STOP
                    END
为什么这个程序运行出来和课本上的结果不一样，课本上的结果time=12.5,       25    37.5   37.75