Question

This is actually the program my instructor had provided with us to work with, i had to make several changes thus far to get it to at least compile:

 #include <dirent.h>
#include <errno.h>
#include <stdio.h>
#include <cstdlib>
#include <iostream>
#include <cctype>
#include <cstdio>
#include <string>
#include <list>

using namespace std;
std::string makeString();
std::string path= "/";
DIR*dirp;
struct dirent*direntp;
std::list<string> child_directories;



void dir_traverse(&path, ios::out){
    list<string> child_directories;
    DIR*dirp = opendir(path.data());
    struct dirent*dir_entry = readdir(dirp);
        while(dir_entry !=null){ 
             unsigned char d_type = dir_entry->d_type==DT_OIR?'D' : 'R';
             if(d_type == 'D'){ 
                if(dir_entry->d_name[0]!= '.')
                    {
                    child_directories push_back(dir_entry_d_name);
                }

             }
            out<<'\t'<<d_type<<":"<<dir_entry->d_name<<endl;
            dir_entry= readdir(dirp);
        }
        list<string>::iterator it = child_directories.begin();
        while(it! = child_directories.end())
            {
                dir_traverse(&path + "/" + *it, out);
                it++;
            }
        closedir(dirp);
}

I get the error I have as the title in reference to the dir_traverse function. I am pretty much interested in figuring out what is causing the problem and why. Half of what is going on in the function I don’t really get at the moment, which is probably why I am having this compiling issue. just not up to speed on c/c++ yet 🙂

thanks

edit:

void dir_traverse(string& path, ostream& out){
    list<string> child_directories;
    DIR*dirp = opendir(path.data());
    struct dirent*dir_entry = readdir(dirp);
        while(dir_entry !=NULL){ 
             unsigned char d_type = dir_entry->d_type==DT_DIR?'D' : 'R';
             if(d_type == 'D'){ 
                if(dir_entry->d_name[0]!= '.')
                    {
                    child_directories.push_back(dir_entry_d_name);
                }

             }
            out<<'\t'<<d_type<<":"<<dir_entry->d_name<<endl;
            dir_entry= readdir(dirp);
        }
        list<string>::iterator it = child_directories.begin();
        while(it != child_directories.end())
            {
                dir_traverse(&path + "/" + *it, out);
                it++;
            }
        closedir(dirp);
}

Answer 1

Okay, so you need to make a few changes to your instructor’s sample to get it to compile.

I’m going to assume you’ve included the four headers needed to compile. I recommend you pull in just the following four symbols from the std namespace, rather than the whole lot. Personally I prefer to refer to std::string in my code.

using std::string;
using std::ostream;
using std::list;
using std::endl;

Anyway, only the following three lines need to be fixed:

void dir_traverse(string& path, ostream& out) 

Should be…

void dir_traverse(const string& path, ostream& out)

Because you later pass in a temporary when you call the function recursively.

            child_directories.push_back(dir_entry_d_name); 

Should be…

            child_directories.push_back(dir_entry->d_name);

This looks like a typo!

    dir_traverse(&path + "/" + *it, out);

Should be…

    dir_traverse(path + "/" + *it, out);

This looks like a typo, too. This is where you create the temporary path string that I mentioned earlier. This must be passed as a const reference (since it is not passed by value).

As you practise more, you’ll become more attuned to your compiler’s error messages!

Good luck!