CODEWITHSUNDEEP
c++qt
Ilya Telefus
Ilya Telefus

Reputation: 39

How to solve undefined reference to own C++ member function?

I have written function for splitting sentence to words, but something went wrong after I wanted to work with it. mainwindow.cpp :

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <qdebug.h>
#include <vector>
#include <iostream>
using namespace std;
vector <QString> myvector;
vector<string>::iterator it;

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}
MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_addButton_clicked()
{
    QString str = ui->textEdit->toPlainText();
    //qDebug() << str;
    vector<string> v = split(str.toStdString());
    for(int i = 0; i < myvector.size(); i++){
        ui->listWidget->addItem(myvector[i]);
    }

}

vector<string> split(const string s)
{
   vector<string> myvector;
   typedef string::size_type string_size;
   string_size i = 0;
   while (i != s.size()) {
      while (i != s.size() && isspace(s[i]))
         ++i;
      string_size j = i;
      while (j != s.size() && !isspace(s[j]))
         j++;
      if (i != j) {
         myvector.push_back(s.substr(i, j - i));
         i = j;
      }
   }
   return myvector;
}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <vector>
#include <iostream>
using namespace std;
namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
    std::vector<string> split(const string s);

private slots:
    void on_addButton_clicked();

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

here is error :

undefined reference to MainWindow::split(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)

Upvotes: 0

Views: 826

Answers (1)

Martin Bonner supports Monica
Martin Bonner supports Monica

Reputation: 28987

You declare a member function in MainWindow and then use it, but you define:

vector<string> split(const string s)

That is a standalone function. Probably easiest to change to:

vector<string> MainWindow::split(const string s)

A better solution though, would be to declare split outside of the MainWindow class (it has nothing to do with MainWindow, it is just a useful litte utility function), and leave the definition alone.

I would also change the argument to be const string& s, to save having to copy the string (and I concur with Bathsheba - use a std::unique_ptr to take care of deleting).

Upvotes: 2

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