题目：点击按钮改变文字

需要增加一个count属性，并且只需要定义槽，信号函数已经内置好了

//widget.h#ifndef WIDGET_H
#define WIDGET_H#include <QWidget>QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACEclass Widget : public QWidget    //窗体对象
{Q_OBJECTpublic:Widget(QWidget *parent = nullptr);~Widget();int count;    //计数public slots:void pushBtn(void);    //接收槽private:Ui::Widget *ui;
};
#endif // WIDGET_H

//widget.cpp#include "widget.h"
#include "ui_widget.h"
#include <QDebug>Widget::Widget(QWidget *parent): QWidget(parent), ui(new Ui::Widget)
{ui->setupUi(this);count=0;    //初始化count//绑定信号与接收槽connect(ui->pushButton_3,SIGNAL(clicked()),this,SLOT(pushBtn()));connect(ui->pushButton_4,SIGNAL(clicked()),this,SLOT(pushBtn()));
}Widget::~Widget()
{delete ui;
}void Widget::pushBtn()
{count++;
//    qDebug()<<"count="<<count;QString str=QString("你点击了%1次").arg(count);   // 类似printfui->label->setText(str);}