C++ program whose output is two C++ programs?

My current task right now is to write one program which takes as input some textual specification for the compression of 64 bit instructions into 32 bit instructions. From that specification I am to build two executable programs: an encoder and a decoder.

Currently I'm just writing a parser class to tokenize the textual specification I've designed, but eventually I will have to turn the information I get into the two new programs. The only way I know I could do it is print out to a new .cpp file using ofstream then using system('g++ new_file.cpp -o new.x') to create the executable. Then perhaps system('rm new开发者_StackOverflow社区_file.cpp') to clean up.

I have looked around all over for other ways to do this, but have found nothing. If you have any advice to give, I'd be very grateful.

Thanks

p.s. I didn't include any of my code because the code is irrelevant. For simplicity's sake my goal could be to write a program whose output is a "Hello, World!" -esque executable.

---

Have your program do this:

#include <iostream>
#include <fstream>
#include <cstdlib>
using namespace std;

int main() {
    {
    ofstream out( "a.cpp" );
    out << "#include <iostream>\nint main() { std::cout << \"hello world\\\n\"; } \n";
    }
    system( "g++ a.cpp -o hello" );
}

Just tested this - it does produce a compiled hello world program.

---

Hmm, sounds like a nice task for a bit of XML and XSLT. Use XML to define what you want, and XSLT to generate the actual C++ code.

EDIT: For those who downvoted:

<?xml version="1.0" encoding="UTF-8" ?>
<proggy>
 <prompt input='uname' type='std::string'>
   <text>Name: </text>
   <output><text>Hello </text><field name="uname"/><text>!</text></output>
 </prompt>
</proggy>

The XSL to transform this to C++

<?xml version="1.0"?>

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
  <xsl:output method="text" indent="no"/>

  <xsl:variable name="co"><xsl:text>std::cout</xsl:text></xsl:variable>
  <xsl:variable name="ci"><xsl:text>std::cin</xsl:text></xsl:variable>
  <xsl:variable name="e"><xsl:text> &lt;&lt; std::endl;</xsl:text></xsl:variable>
  <xsl:variable name="so"><xsl:text> &lt;&lt; </xsl:text></xsl:variable>
  <xsl:variable name="si"><xsl:text> &gt;&gt; </xsl:text></xsl:variable>
  <xsl:variable name="nl"><xsl:text>&#xa;</xsl:text></xsl:variable>

  <!-- Root node -->
  <xsl:template match="/">
    <xsl:text>
#include &lt;iostream&gt;

int main(void)
{
    </xsl:text>
    <xsl:apply-templates select="//proggy"/>
    <xsl:text>
  return 0;
}
    </xsl:text>
  </xsl:template>

  <xsl:template match="proggy">
    <xsl:apply-templates select="prompt"/>
  </xsl:template>

  <xsl:template match="prompt">
    <xsl:value-of select="$co"/><xsl:value-of select="$so"/>
    <xsl:text>"</xsl:text><xsl:value-of select="text"/><xsl:text>"</xsl:text>
    <xsl:value-of select="$e"/><xsl:value-of select="$nl"/>
    <xsl:value-of select="@type"/><xsl:text> </xsl:text><xsl:value-of select="@input"/><xsl:text>;</xsl:text>
    <xsl:value-of select="$nl"/>
    <xsl:text>if (</xsl:text>
    <xsl:value-of select="$ci"/><xsl:value-of select="$si"/><xsl:value-of select="@input"/>
    <xsl:text>){</xsl:text>
    <xsl:value-of select="$nl"/>
    <xsl:apply-templates select="output"/>
    <xsl:value-of select="$nl"/>
    <xsl:text>}</xsl:text>
  </xsl:template>

  <xsl:template match="output">
    <xsl:value-of select="$co"/>
    <xsl:apply-templates select="./*" mode="so"/>
    <xsl:value-of select="$e"/>
  </xsl:template>

  <xsl:template match="text" mode="so">
    <xsl:value-of select="$so"/><xsl:text>"</xsl:text><xsl:value-of select="."/><xsl:text>"</xsl:text>
  </xsl:template>

  <xsl:template match="field" mode="so">
    <xsl:value-of select="$so"/><xsl:value-of select="@name"/>
  </xsl:template>

</xsl:stylesheet>

I challenge you to write a smaller C++ program to generate the same C++ code! And this is a trivial example.