Use the C$++$ library $$regex$$ to implement the following application:

Your program should read input string from a text file $($input$.$txt$)$ that contains $100$ lines. When the program is executed, it should print the following statistics about these keywords $$Error$,$error$,$Errors$,$errors$,$ or $$eror$$:

$1.$ User enters a line number and the program prints the number of keywords in that line.

$2.$ The number of lines containing at least one of the keywords.

$3.$ The line number$($s$)$ containing the maximum number of keywords.

$4.$ The line number$($s$)$ for the lines starting with these keywords

Note: the numbering of the lines starts with $0.$

Download the source code $$prog$-$ex$-$toc.cpp$$ and run it to see how it should work. Then, read the comments to see where to put your code.