7 replies to this topic

[rainwater_stillicide]

In the language of your choice: write a program which will output it's own source code.

[lintwurm]

This is my c++ way of doing it...

Spoiler

#include <iostream>
#include <fstream>

using namespace std;

int main()
{
cout<<"This program will output its own sourcecode... (Hopfully)"<<endl;
ifstream reader;
string line;
reader.open("hello.cpp");
if (reader.is_open())
{
while (! reader.eof() )
{
getline (reader,line);
cout << line << endl;
}
reader.close();
}

else cout << "Unable to open file";
}

Not sure if this is the best way, but it works

[rainwater_stillicide]

Nice. Ambitious hacker solution.

Can anyone write a version that doesn't need to read from it's own source file?

[JBu92]

in python:

Spoiler

filename = "selfsrc.py" # or whatever you name the script
filename2 = "output.txt"
file1 = open(filename, "r")
file2 = open(filename2, "w")
txt = file1.read()
file2.write(txt)
file1.close
file2.close

it outputs to file, but you could output to shell instead, if you wanted

[FLW_FTW]

In the language of your choice: write a program which will output it's own source code.

Question: Does the outputted source code have to be able to then be compiled and repeat the objective? I can get the printing of the sourcecode to work, but I lose all formatting.

See my answer:

Spoiler

#include <stdio.h>

char source[] = "#include <stdio.h>"
"char source[] = \"%s\";"
"int main()"
"{"
"	printf( source, source );"
"	return 0;"
"}";

int main()
{
	printf( source, source );
	return 0;
}

output:

(10:18 PM Tue Mar 09)
(w@w.domain1)-(~/dev/C/Projects/BinRevChallenges)>./tricky001
#include <stdio.h>char source[] = "#include <stdio.h>char source[] = "%s";int main(){	printf( source, source );	return 0;}";int main(){	printf( source, source );	return 0;}

Edited by FLW_FTW, 10 March 2010 - 01:20 AM.

[rainwater_stillicide]

In the language of your choice: write a program which will output it's own source code.

Question: Does the outputted source code have to be able to then be compiled and repeat the objective? I can get the printing of the sourcecode to work, but I lose all formatting.

See my answer:

Spoiler

#include <stdio.h>

char source[] = "#include <stdio.h>"
"char source[] = \"%s\";"
"int main()"
"{"
"	printf( source, source );"
"	return 0;"
"}";

int main()
{
	printf( source, source );
	return 0;
}

output:

(10:18 PM Tue Mar 09)
(w@w.domain1)-(~/dev/C/Projects/BinRevChallenges)>./tricky001
#include <stdio.h>char source[] = "#include <stdio.h>char source[] = "%s";int main(){	printf( source, source );	return 0;}";int main(){	printf( source, source );	return 0;}

This is a good attempt and is along the right lines. Ideally the output would be identical to the source file (there's nothing stopping you smooshing the original source file onto one line if you like).
The problem with this solution isn't the formatting though (C ignores whitespace generally so even if a program is all on one line it'll still compile). it's that inside the strings the '\'s you use to escape \"%s\" aren't repeated and that you some quotation marks are lost etc...

Keep working at it, it's close to a full solution.

[z3ros3c]

In Python:

(saved as 'file.py')

#!/usr/bin/env python
print(open('file.py','r').read())

OR if you want to do it the PROPER way:

x='x=%s;x%%`x`';x%`x`

[heisenbug]

In Perl:

Spoiler

#!/usr/bin/perl
open FILE, "<$0" or die $!;
while (<FILE>) {print $_;}