[Resolved] Vector help

Code:

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              eANum[i] = hold[0];
              eAMass[i] = hold[1];
              eName[i] = hold[2];
              eSymbol[i] = hold[3];

---

In the above code eANum etc are string arrays and hold is a vector, I try to assign the array of strings to a vector element, however, when I run the executeable it crashes, and I know it is this part because I commented it out and it ran fine.

could u show the rest of the code?

Code:

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#include <fstream>
#include <conio.h>
#include <algorithm>        // container manipulation
#include <string>                // easy strings
#include <vector>                // growable array
#include <string>

using namespace std;

void split_string(const string &s, vector<string> & out, char split_at);

int main()
{

  string incoming;
  int search;

  string eANum[105];
  string eAMass[105];
  string eName[105];
  string eSymbol[105];
  vector<string> hold;

  int i;
  int j;
  int k;

  ifstream infile;

  infile.open("a:\\elemental.txt", ios::in);

  if (!infile)
          {
              cout << "Fatal Exception: File could not be opened." << endl
                  << "Press any key to terminate...";
        while (!kbhit());
      }
  else
          {
              for (i = 0; i <= 104; i++)
                {
              hold.resize(0);

                              infile >> incoming;

              split_string(incoming, hold, ';');

              eANum[i] == hold[0];
              eAMass[i] == hold[1];
              eName[i] == hold[2];
              eSymbol[i] == hold[3];
            }

      }

  cout << "Enter a way to search: " << endl
        << "1. Search by atomic number." << endl
        << "2. Search by atomic mass." << endl
        << "3. Search by element name." << endl
        << "4. Search by element symbol." << endl;

  cin >> j;

  if (j == 1)
          {
              cout << "Enter an atomic number to search for." << endl;
        cin >> search;
    }
  else if (j == 2)
          {
              cout << "Enter an atomic mass to search for." << endl;
        cin >> search;
    }
  else if (j == 3)
          {
              cout << "Enter an element name to search for." << endl;
        cin >> search;
    }
  else
          {
              cout << "enter an element symbol to search for." << endl;
        cin >> search;
    }
   
       

  return 0;
}

void split_string(const string &s, vector<string> & out, char split_at)
{
        // for searching the string
        string::const_iterator stay, run;
        // set stay to the start of the string
        stay = s.begin();
        // temporary
        string t;
        // loop run through the string, from front to back
        for(run=stay; run != s.end(); ++run)
        {
                // if encountered split char...
                if(*run == split_at)
                {
                        // ...clear the temporary value...
                        t = "";
                        // (speeds it up a little)
                        t.reserve(run-stay);
                        // ..., copy current substring to temporary...
                        t.append(stay, run);
                        // ...and add it to the array.
                        out.push_back(t);
                        // Finally, let the next substring begin directly after the splitting char.
                        stay = run+1;
                }
        }
        // same as above for the last piece (from last split char to end of string)
        t = "";
        t.reserve(run-stay);
        t.append(stay, run);
        out.push_back(t);
}

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The split function is corned bee's function so I know that is not the problem.

Code:

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eANum[i] == hold[0];
eAMass[i] == hold[1];
eName[i] == hold[2];
eSymbol[i] == hold[3];

---

should be

Code:

---

eANum[i] = hold[0];
eAMass[i] = hold[1];
eName[i] = hold[2];
eSymbol[i] = hold[3];

---

= is the assignment operator, == is the comparison operator.

I tried that, but it still crashes, any ideas?

Where does it crash? Do you know how to use a debugger?

I have no idea why exactly it crashes but I do know it is the piece of code I initially posted.

Edit:

When I attempted to debug it it pointed me to this line:

Code:

---

basic_string<charT, traits, Allocator> &
basic_string<charT, traits, Allocator>::operator= (
  const basic_string<charT, traits, Allocator>& str)
{
    str.pref()->addReference();  // This line
    pref()->unLink(alloc_);
    data_ = str.data_;
    return *this;
}

---

That's just the assignment operator for the standard string, so that's of no help since you already know that it crashes when you assign a certain value to one of those strings.

As CB said, try to use a debugger and check what the variables are and on exactely what line it crashes

Alright I will give it a try.

Well when I run debugger I get an error at the following line:

eAMass[i] = hold[1];

Also, when I do something like this:

Code:

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              eANum[i] = hold[0];
              cout << "Got to step 1\n";
              eAMass[i] = hold[1];
              cout << "Got to step 2\n";
              eName[i] = hold[2];
              cout << "Got to step 3\n";
              eSymbol[i] = hold[3];
              cout << "Got to step 4\n";

---

It prints the "Got to step 1" line and then it crashes. So I think that after it first assigns to eANum it crashes.

Code:

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eAMass[i] == hold[1];

---

Are you sure there's a second element in the vector hold?

The error is not at eANum since it does print got to step 1

Also try to check what hold[1] contains when you try to add it to the string!

Yea this c++ business really frys my brain in VB I would have had this solved so fast. I will continue to try.

Well I am sure that it is filling the vector correctly because I tested it out without the loop and everything and it printed the entire file split at the semi-colon

Yeah but it's not the prob at the first item of the vector, it occurs at the second (or have you used without the loop while accessing hold[1] ? )

Also can you maybe attach the file you're trying to read? So that we can test it over here and see what the prob is?

Alright I will attach it, however, I think there is something weird going on because when I split it and read through each item in the vector it works fine but then assigning doesnt.

Tried it here, runs without any crashes / runtime errors... what compiler are you using?

also:

Code:

---

  if (!infile)
          {
              cout << "Fatal Exception: File could not be opened." << endl
                  << "Press any key to terminate...";
        while (!kbhit());
        return 1
      }

---

You'd want the code to terminate ;)

And I recommend not to use conio.h, include <iostream> (for cin and cout) and use

Code:

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system("pause");

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instead of

Code:

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while (!kbhit());

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And consider using a switch statement rather than your if - elseif

I have no idea how you did that, but wow, thanks :D, I mean, it looks exactly like my old code in most respects I can't even find the major difference!

Sorry to burden you again, but say I want to search through and compare a string to a float value, how would I go about converting the string to float? I tried using atof but I didn't have much luck (errors).

Something like this?

Code:

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int main()
{
string s = "1.007";
float f = atof(s.c_str());
cout << f;
}

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I got it to work, I just decided to change the search variable to a string rahter than having it a float =/