Chapter 10, Problem 4SA

Output file:

A file where the data are written is called as “output file”. The output file is created on the disk and allows the program to write a data to it.

Append mode:

• Append mode is used to write a data at the end of the file.
• The ‘a’ mode is used to open an output file with appending option.
• If the specified file does not exists in the disk, then the new empty file with same name is created on same location and the data will be written to it.

Existing file is opened in append mode:

• If the existing file is opened in an appending mode, then the contents will be written at the end of the file.
• The existing contents will not be erased from the file and the new contents will be added with existing contents at end of the file.

Example Program:

The following program is used to open an output file, and append the contents into the file:

#Function main

def main():

#Open a file

    numberfile=open('number_list.txt','a')

#Append the numbers into file

#Append 200 into file

    numberfile.write(str(200)+"\n")

#Append 250 into file

    numberfile.write(str(250)+"\n")

#Append 300 into file

    numberfile.write(str(300)+"\n")

#Close the file

    numberfile...