Re: ostream output - indenting

From:
Joe Greer <jgreer@doubletake.com>
Newsgroups:
comp.lang.c++
Date:
Mon, 28 Jul 2008 18:10:25 +0000 (UTC)
Message-ID:
<Xns9AE9902EFB47Cjgreerdoubletakecom@85.214.90.236>
Christopher <cpisz@austin.rr.com> wrote in news:dfc7ee09-8cdf-4e7d-b8f0-
69531c079930@34g2000hsf.googlegroups.com:

How would I go about indenenting for each level of recursion, if I am
trying to output the contents of a class which contains its own type?

where AttributeGroupMap is
typdef std::map<std::string, AttributeGroup *> AttributeGroupMap;

const std::string AttributeGroup::ToString() const
{
   std::stringstream ss;

   ss << m_name << std::endl;

   for(AttributeGroupMap::const_iterator it =
m_attributeGroups.begin();
        it != m_attributeGroups.end(); ++it)
   {
      // need everything from here indented for each level of
recursion
      ss << (it->second)->ToString() << std::endl;
   }

   return ss.str();
}

I thought if changing the parameters to something like
const std::string AttributeGroup::ToString(unsigned indent = 0) const

and then
ss << /** do something to indent here */ (it->second)-

ToString(indent + 3) << std::endl;


but still don't know how to indent the entire thing.


Indenting is pretty simple, simply prepend std::string(indent, ' ') to
the string. If I were you though, I would separate the recursive output
from the ToString() method. A method named ToString() is too general
for such a specific use. I would start with something like:

// since we return by value, there is no need to return a const string
std::string AttributeGroup::ToString() const
{
   return m_name; // assumes m_name is a string
}

std::string AttributeGroup::RecursiveAttributeDump(int lvl) const
{
   std::string ret = std::string(lvl * 3, ' ') + ToString() + '\n';

   for (AttributeGroupMap::const_iterator it = m_attributeGroups.begin
(),
      it != m_AttributeGroups.end(), ++it)
   {
      RecursiveAttributeDump(lvl+1);
   }
   return ret;
}

This is all untried but it should work.

joe

}

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