Thread: why error??

Here is some code which I can not understand why I get an error.

This is the error I get from Visual C++
(30) : error C2679: binary '<<' : no operator defined which takes a right-hand operand of type 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' (or there is no acceptable conversion)

What am I doing wrong??

It is just reading some text from a file, putting it into a struct, then in to a vector. Now I would like to read what is in the vector.

Would appreciate any pointers.
Thanks



#include <iostream.h>
#include <stdlib.h>
#include <vector>
#include <fstream>
#include <string>
#include <sstream>
#include <cctype>
#include <cstdlib>

using namespace std;

struct course
{
string name;
string num;
int credits;
vector <string> preq;
};

vector <course> read_catalog(vector<course> &catalog);

int main()
{
vector <course> catalog;

read_catalog(catalog);
//system("PAUSE");

for(int i=0; i<catalog.size(); i++)
cout << catalog[i].name << endl;

return 0;

}

vector <course> read_catalog(vector <course> &catalog)
{
string line, part;
int counter;
course c;

ifstream fin("catalog.txt");

if(fin.fail())
{
cout<<"Failure to open file";
return catalog;
}



while(!fin.eof())
{
getline(fin,line); //taking in a whole line from file
stringstream sin(line); //converting string line to a stream
counter=1;
while(true)
{
getline(sin, part, ','); //taking a line until a comma is found
if(part=="")
break;
if(counter==1)
c.name = part;
if(counter==2)
c.num = part;
if(counter==3)
{
const char *st = part.c_str(); //string part is convert to cstring
c.credits = atoi(st); //st is converted to an integer and put in struct
}
if(counter>3)
(c.preq).push_back(part);
counter++;
}
}

return catalog;
}

you smarter guys can correct me if im wrong, but if you use a struct or class to define a data type, you cant use the << or >> operators unless you overload them.

okay made a few changed, but still stuck, looks like in inner loop

i am trying to convert a string to a stream, then use getline to extract part of by string to the comma, but it doesn't seem to be working

any ideas

catalog.txt has lines like:

"Intro to C, CS101, 3, CS100"

Code:

#include <iostream.h>
#include <stdlib.h>
#include <vector>
#include <fstream>
#include <string>
#include "sstream.h"

using namespace std;

struct course
  {
  string name;
  string num;
  int credits;
  vector <string> preq;
  };

vector <course> read_catalog(vector<course>&catalog);

int main()
{
  vector <course> catalog;
  read_catalog(catalog);
      system("PAUSE");
      return 0;
}

vector <course> read_catalog(vector <course> &catalog)
 {
 string line, part;
 int counter;
 course c;

  ifstream fin("catalog.txt");

  if(fin.fail())
     {
     cout<<"Failure to open file";
     return catalog;
     }



  while(!fin.eof())
       {
        getline(fin,line);       //taking in a whole line from file
        // is this right???????????????????????????????????
        stringstream sin(line);  //converting string line to a stream
        counter=1;
        while(true)
          {
           getline(sin, part, ',');  //taking a line until a comma is found
           if(part.size()==0)
             break;
           if(counter==1)
             c.name = part;
           if(counter==2)
             c.num = part;
           if(counter==3)
             {
             const char *st = part.c_str();   //string part is convert to cstring
             c.credits = atoi(st);     //st is converted to an integer and put in struct
             }
           counter++;
           }
           catalog.push_back(c);

           /* if(counter>3)
             (c.preq).push_back(part);      // ????? is this right??????     */
        }
        cout << line << endl;
  return catalog;
 }

this i got to compile in bloodshed, by the way