Text program

[Caleb.Carlton]

I need to make a program that opens a file full of proxies, for example

123.123.123.255:1080
123.123.123.123:1080
123.123.123.255:1080
123.123.123.123:1080

And take off the :1080

Any help would be much appreciated. Thank you.

[redhead]

#!/bin/sh
cat $1 | sed 's/:1080//g'

if you want some other way, be more specific as to if it's C or C++, since file handling is a bit different.
Perhaps you should look at opening file, reading in, string handling, and output. Then try to make something happen, if all fails, give us your suggestion and we will correct it, maybe even come with the solution.

[Caleb.Carlton]

Sorry about the confusion, I was looking for information on how to do it in C++. Thank you for your help redhead.

[redhead]

something like this?

#include <iostream>
#include <fstream>
#include <string>

using std::cout;
using std::endl;

const int line_length = 200;

int main(int argv, char* argc[])
{
  char buffer[line_length];
  if(argv != 2)
    {
      cout << "Usage: " << argc[0] << " <filename>" << endl;
      return -1;
    }

  ifstream file (argc[1], ios::in);
  if (!file.is_open())
    {
      cout << "Error: opening file " << argc[1] << endl;
      return -1;
    }
  while (!file.eof() )
    {
      file.getline(buffer, line_length -1);
      strtok(buffer, ":");
      cout << buffer << endl;
    }
  file.close();
  return 0;
}

The use of strtok() should be thought through, since what I use it for here is using it's bad sideeffect for a good thing(tm).
strtok() changes it's first argument uppon first call, this will result in whatever is placed befor the : will remain in buffer, for a better usage, you'd probaly change it to:

int main(int argv, char* argc[])
{
  char buffer[line_length];
  char *ptr;
  if(argv != 2)
...
  while (!file.eof() )
    {
      file.getline(buffer, line_length -1);
      ptr = strtok(buffer, ":");
      cout << ptr << endl;
...

In this way you can make a check to see if it's a valid token found by strtok().

If you want it to show the port aswell, but seperated from the IP number, this might be useful:

...
  while (!file.eof() )
    {
      file.getline(buffer, line_length -1);
      ptr = strtok(buffer, ":");
      while(ptr != NULL)
        {
          cout << ptr << endl;
          ptr = strtok(NULL, "\t :");
        }
    }
...

This will also make a <tab> or <space> delimited file readable.

[Valmont]

I am just dropping by like the wind, in the mood for some relaxing code. I'll attend to unsolved posts later.

This part I wouldn't reccomend:

while (!file.eof() )

Actually it *might* be wrong to do such a thing. I'll explain.
The EOF-bit is set when the file reaches PAST the end-of-file! So the while loop checks one time too often for the true end of file. That is not persé wrong. The program still works. In fact, with simple file i/o operations there is nothing wrong with this.

But in general...
The eof-bit might not always be set! Therefore, this kind of testing in a loop is not ok.
If the input is mapped to a device, then it is not possible for C++ to predict what the last input was.

I'll get to the solution in a moment. First another thing.

ifstream file (argc[1], ios::in);
  if (!file.is_open())

In the first line, ios::in is not needed right now, since it is the default parameter for istream anyway. Just a heads up.
In the second line, testing explicitly with is_open() is not needed right now too. That means style-wise it is not needed. Since the handle to istream already knows the name of the file, we can use the overloaded operator!() for the ifstream class.

See code below for "solution" to these issues. The app by itself deals only with files as presented in the very first post by Caleb.Carlton, wich assumes correct "IP:port" format. Tabs, spaces etc will be dealt with correctly as well. An IP like "000" isn't usually defined by many programs, but both 0.0.0.0:port as well as 000.000.000.00:port will work.
You could implement features to check for correct ip:port formats but that wasn't asked by the poster, so I didn't.

#include <iostream>
#include <string>
#include <fstream>
#include <cstring>


using std::cout;
using std::endl;
using std::ifstream;
using std::string;
using std::getline;
using std::size_t;

int main(int argv, char* argc[])
{
   if(argv != 2)
   {
      cout << "Usage: " << argc[0] << " <filename>" << endl;
      return -1;
   }

   ifstream file(argc[1]);
   if (!file)
   {
     cout << "Error: opening file " << argc[1] << endl;
     return -1;
   }
   
   string ipNumber;
   while ( file>>ipNumber )
   {
      size_t pos;
      pos = ipNumber.rfind(":");
      ipNumber.erase(pos, ipNumber.size()-1);
      cout << ipNumber << endl;
   }
   
   //If file-reading loop exits before an EOF has been reached, something is wrong.
   if(!file.eof())
   {
      cout<<"ERROR: Something went wrong during processing of file."<<endl;
   }
   
   file.close();
   return 0;
}