比较两个平面文件的记录，并将FILE-1的不匹配记录写入输出

Question

我有两个文件File-1和File-2。两个文件中的记录都是按降序排列的。File-1的顶部可能有一些额外的记录。我想写入File-1中不存在于File-2中的所有记录。

File-1:- Sample
2019-08-06 XXXX
2019-08-06 XYXX
2019-08-06 XXYX
2019-08-05 XXYX
2019-08-05 XXYY
2019-08-04 XXYX
2019-08-03 XXYX
2019-08-03 XZYX

File-2:- Sample
2019-08-05 XXYX
2019-08-05 XXYY
2019-08-04 XXYX
2019-08-03 XXXX
2019-08-03 XZYX


Output:-
2019-08-06 XXXX
2019-08-06 XYXX
2019-08-06 XXYX
2019-08-03 XXYX

请让我知道伪码。

Answer 1

Open both input files for reading
Open output file for writing
while not eof file2
read file2
    while file1 > file2 and not eof file1
        read file1
        write file1 to output
    end while  
end while

Answer 2

PERFORM 000-OPEN.
PERFORM 100-PROCESS THRU 100-PROCESS-EXIT
UNTILL END-File-1 AND END-File-2. (Where END-File will be declare as PIC X(2) VALUE '10')
PERFORM 200-CLOSE-FILE THRU 200-CLOSE-FILE-EXIT.
*************************************************************
000-OPEN.
will perform opening the 2 files in INPUT mode and 3 output file in OUTPUT 
mode.
000-OPEN-EXIT.
**
100-PROCESS.
**
will perform READ operation for 2 input files, then will compare first 
record from both files.

IF File-1(REC-1) NOT= File-2(REC-1)
WRITE File-3 (For unmatched Records)
READ File-1 AND File-2.
END-IF.