Can any programs read a text file into c++ code? - file

Question

Is it possible for a program to open up a text file and use it as c++ code? If so, how? What if a program wanted to append code from a text file to itself? Can that happen?
Thanks!

Answer 1

Depends on what you mean by "text file" and "use it as c++ code." If by "text file" you mean a file containing uncompiled C++ code, and by "use it as C++ code" you mean execute it, the answer is no, you'd need to compile it first before it's of any real use (unless you want to write some sort of interpreter or compiler).
With regards to your second question, I suppose it's possible, but it'd be really hard because you would need to compile the C++ code in that text file into binary, then insert it into the program in a meaningful way.
If you're doing this just for curiosity, you might have better luck with an interpreted language (such as Perl or Ruby). I was a bit curious myself, so I took a stab at the problem with the following ruby script (saved in alpha.rb):
File.open('alpha.rb', 'a') do |file1|
file1.puts "\nprint 'Sneaky Addition!'";
end
After you run it, you'll see that a new line of code has been added. If you run it a second time, it'll run the code. I believe the reason that it isn't run the first time is that the file is already loaded into Ruby when it's run, so it doesn't see the change to the file until it reloads it.
Of course, we could possibly get around this by using a second file (as explained here)...
Alpha.rb
print "Alpha running...\n"
File.open('beta.rb', 'a') do |beta|
beta.puts("\nprint \"But alpha got the last word.\\n\"")
end
load 'beta.rb';
Beta.rb
print "Beta running...\n"
File.open('alpha.rb', 'w') do |alpha|
alpha.puts("print \"Sneaky Beta addition.\\n\"")
alpha.puts("\nprint \"Beta overwrote alpha!\\n\"")
alpha.puts("\nprint \"This code only works once =) \\n\"")
end
load 'alpha.rb'
I suppose you might be able to do something similar in C++, but it'd be much more complicated since you would be compiling your code into binary, and even then you probably can't just append it.