程序无法写入FORTRAN中的文件

Question

我一直在和FORTRAN纠缠不清，决定编写一个简单的Blackjack程序，在文件中保存赢/输统计信息。 问题是，每次执行程序时，它都会写入一个新数组，而不是覆盖文件中的现有数组。

相关代码段：

open(15, file='placar.dat')            !opens the file containing a (0,0,0,0) array
integer, dimension(1:4)::round=0'      !This is the array which contains the stats for a 
subroutine r(v)                        !given round, e.g.: player 1 wins and player
integer, intent(in),dimension(1:4)::v  !2 loses, round(1)=1, 
integer, dimension(1:4)::vx            !round(2)=0, round(3)=0, round(4)=1
read(15,*)vx                           !This line reads the array contained in the file to 
                                       !the array vx.
do i=1,4,1
     vx(i)=vx(i)+v(i)                  !this will add the round statistics passed to this 
end do                                 !subroutine to the vx array.
write(15,*)(vx(i),i=1,4)               !this line should overwrite the old array contained
end subroutine r                       !in the file with the new values. But this does not 
                                       !happen and a new line is written.

Answer 1

我相信您的错误来自以下事实：读取原始数组会使文件游标前进。 因此，当您写回文件时，光标已经经过数组。

我相信倒带（将光标设置到初始点）将纠正此问题：

open(15, file='placar.dat')            !opens the file containing a (0,0,0,0) array
integer, dimension(1:4)::round=0'      !This is the array which contains the stats for a 
subroutine r(v)                        !given round, e.g.: player 1 wins and player
integer, intent(in),dimension(1:4)::v  !2 loses, round(1)=1, 
integer, dimension(1:4)::vx            !round(2)=0, round(3)=0, round(4)=1
read(15,*)vx                           !This line reads the array contained in the file to 
                                       !the array vx.
do i=1,4,1
     vx(i)=vx(i)+v(i)                  !this will add the round statistics passed to this 
end do                                 !subroutine to the vx array.
rewind(15)                             !rewind file
write(15,*)(vx(i),i=1,4)               !this line should overwrite the old array contained
end subroutine r                       !in the file with the new values. But this does not 
                                       !happen and a new line is written.

但是请注意，这将覆盖从文件开头开始的内容，因此，如果该文件中不仅包含数组，还将覆盖您的其他内容，也许会使输出看起来很奇怪。