Answer
See the explanation
Work Step by Step
To modify the algorithm in Figure 9.15 to handle the case where both input files contain a record with the same key field value, you can follow these steps:
1. When reading records from both input files, compare the key field values.
2. If the key field values are the same, only output one of the records to the output file.
3. Continue reading records from both input files until all records have been processed.
Here's a pseudocode example of how you can modify the algorithm:
```
open input file1
open input file2
open output file
read record1 from file1
read record2 from file2
while record1 != EOF and record2 != EOF:
if record1.key == record2.key:
write record1 to output file
read record1 from file1
read record2 from file2
elif record1.key < record2.key:
write record1 to output file
read record1 from file1
else:
write record2 to output file
read record2 from file2
# Output any remaining records from file1
while record1 != EOF:
write record1 to output file
read record1 from file1
# Output any remaining records from file2
while record2 != EOF:
write record2 to output file
read record2 from file2
close input file1
close input file2
close output file
```
This modified algorithm ensures that only one record with the same key field value from both input files will appear in the output file.
