File handling

Question 1

What is a file and its rules?

Answer 1

• A serial file (simplest file) is one in which data has been stored in the order in which it occurred.
• To write to a file, either create a new file or append to the end of the file line by line.
• To search in a file (read), start at the top of the file and read line by line until you find what you are looking for or reach the end of the file.
• Data cannot be deleted or changed in the file directly. Instead create a new file and copy all the lines (inserting any changes), except the lines to be deleted, to the new file.
• You cannot read or write to a file at the same time.

Question 2

How to read one line from a file in pseudocode?

Answer 2

myFile = openRead(“test.txt”)
line = myFile.readLine()
myFile.close()

Question 3

How to print all lines from a file in pseudocode?

Answer 3

myFile = openRead(“sample.txt”)
while NOT myFile.endOfFile()
print(myFile.readLine())
endwhile
myFile.close()

Question 4

How to write one line to a file in pseudocode?

Answer 4

myFile = openWrite(“sample.txt”)
myFile.writeLine(“Hello World”)
myFile.close()