Question

Is there a way I can write text to a file from a certain point in the file?

For example, I open a file of 10 lines of text but I want to write a line of text to the 5th line.

I guess one way is to get the lines of text in the file back as an array using the readalllines method, and then add a line at a certain index in the array.

But there is a distinction in that some collections can only add members to the end and some at any destination. To double check, an array would always allow me to add a value at any index, right? (I’m sure one of my books said other wise).

Also, is there a better way of going about this?

Thanks

Answer 1

Oh, sigh. Look up the ‘master file update’ algorithm.

here’s pseudocode:

open master file for reading. count := 0 while not EOF do     read line from master file into buffer     write line to output file         count := count + 1     if count = 5 then        write added line to output file     fi od rename output file to replace input file