QMessageBox

#include "dialog.h"
#include "ui_dialog.h"
#include<QMessageBox>

Dialog::Dialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Dialog)
{
    ui->setupUi(this);
}

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

void Dialog::on_pushButton_clicked()
{
    //info
    QMessageBox::information(this,"title here","Text Here");
}

void Dialog::on_pushButton_2_clicked()
{
    //question
    QMessageBox::StandardButton reply;
    reply = QMessageBox::information(this,"title here","Do you like cats?",QMessageBox::Yes|QMessageBox::No);

    if(reply == QMessageBox::Yes)
    {
        QMessageBox::information(this,"title here","You LOVE cats");
    }
}

void Dialog::on_pushButton_3_clicked()
{
    QMessageBox::warning(this,"title here","Waring");
}

void Dialog::on_pushButton_4_clicked()
{
    QMessageBox::StandardButton reply;
    reply = QMessageBox::question(this,"My Title","My Test here", QMessageBox::YesToAll|QMessageBox::Yes|QMessageBox::No|QMessageBox::NoToAll);

    if(reply == QMessageBox::Yes)
    {
        QMessageBox::information(this,"title here","YES");
    }
}