#include "okno.h"
#include "ui_okno.h"

Okno::Okno(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::Okno)
{
    ui->setupUi(this);
    mark = ' ';
}

Okno::~Okno()
{
    delete ui;
}

void Okno::digit (char c)
{
    QString s = ui->lineEdit->text();
    s = s + c;
    ui->lineEdit->setText (s);
}

void Okno::arit (char c)
{
    first = ui->lineEdit->text();
    mark = c;
    ui->lineEdit->setText ("");
}

void Okno::calc ()
{
    QString second = ui->lineEdit->text();

    double a = first.toDouble ();
    double b = second.toDouble ();

    double c = b;

    if (mark == '+')
        c = a + b;
    else if (mark == '-')
        c = a - b;

    QString result = QString::number (c);
    ui->lineEdit->setText (result);
}

void Okno::on_button7_clicked()
{
    digit ('7');
}

void Okno::on_button8_clicked()
{
    digit ('8');
}


void Okno::on_pushButton_clicked()
{
    arit ('+');
}

void Okno::on_pushButton_11_clicked()
{
    calc ();
}