reading different values from a .txt

[melon]

Hey guys,
I´ve read a lot of similar questions here in the last hours, but I still didn´t find out how to do it.
I want to read line by line from a txt file, which contains something like

Hannover Berlin 343.34

in every line.

I´ve ended up with something like this:

 string s,z;
    float g;

    ifstream infile("bsp.txt");

    while(infile >> s >> z >> g){

      k.getQuelle()->setMarkierung(s);
      k.getZiel()->setMarkierung(z);
      k.setGewicht(g);
      insert(k);
    }

But it´s not reading anything from the file.
It would be great if anybody could give me a hint on what I have to change.
Thanks in advance!

[giblit]

maybe try

std::vector<std::string> inputList;
std::string input = "";
while( !infile.eof() )
{
    getline( infile , input );
    inputList.push_back( input );
}

[nedo]

When you have more values on a line, the best/easy way is to read the whole line in a string first, then extract from that string the information you need, based on the pattern you have. In this case before the first space you have a word, after that another word, and after the second space a number(witch you will extract as a substring and then convert to a float
In this topic there was an almost identical problem, unfortunatly the op deleted hi's posts ... but my answer still applies.
http://www.cplusplus.com/forum/beginner/101481/

[Chervil]

Try this:

    ifstream infile("bsp.txt");

    if (!infile.good())
    {
        cout << "File is not open" << endl;
    }

[melon]

Well it does open the file.
@nedo thanks for your answer, but I still don´t understand how to do it. Your example uses linefirst and linelast. Do I have to add the size of the first selected string to get the second? Isn´t there an easier way.

[nedo]

Based on your example, i will assume that all the lines respect this rule:
word, space, word, space, number
if this case you something like this

while(!infile.eof())
{
  double num; // the number
  string firstWord; // first word
  string secondWord; // second word
  string last; // number before transformation to double;
  string line; // the whole line
  getline(infile, line)
  int pos = line.find_first_of(" ", 0); // position of the first space
  firstWord = line.substr(0, pos); // extract the first word
  secondWord = line.substr((pos + 1), line.find_first_of(" ", (pos + 1))); // extract the second word
  pos = line.find_first_of(" ", (pos + 1)); // position of the second space
  last = line.substr((pos + 1), line.find_first_of(" ", (pos + 1))); // the number
  num = atof(last.c_str(); // convert string number to double
}

There might be some errors due to the fact that the code is writen straight in the browser window. See if it works.

Reference to the find_first_of cunction http://www.cplusplus.com/reference/string/string/find_first_of/

[Chervil]

    ifstream infile("bsp.txt");   
    string line;
    
    while (getline(infile, line))
    {
        string s, z;
        float g;
        
        istringstream ss(line);
        ss >> s >> z >> g;

        k.getQuelle()->setMarkierung(s);
        k.getZiel()->setMarkierung(z);
        k.setGewicht(g);
        insert(k);
        // next line for debugging purposes, remove when it is working
        cout << "s: " << s << " z: " << z << " g: " << g << endl;
    }

requires #include <sstream>

[melon]

Hey guys, thank you all for your help. Apparently the version I posted was working already. But without Nedos version I wouldn´t have figured out my mistake, so it helped me anyway. :)