<code c++>
    #include "params.h"
    
    Params::instance().name = ui->lineEdit->text ().toStdString();
    Params::instance().setNumber (ui->spinBox->value());

    Params & p = Params::instance();
    p.getNumber ();
</code>

Soubor params.h
<code c++>
#ifndef PARAMS_H
#define PARAMS_H

#include <string>
using namespace std;

class Params
{
public:
    string name;

private:
    int number;
public:
    int getNumber () { return number; }
    void setNumber (int n) { number = n; }

public:
    Params();

private:
    static int cnt;
    static Params * obj;

public:
    static Params & instance ();
};

#endif // PARAMS_H

</code>

Soubor params.cpp
<code c++>
#include "params.h"
#include <stdexcept>

int Params::cnt = 0;
Params * Params::obj = NULL;

Params::Params()
{
    cnt ++;
    if (cnt > 1)
       throw new runtime_error ("Too many instances");
}

Params & Params::instance ()
{
    if (obj == NULL)
        obj = new Params ();
    return *obj;
}


</code>