问题：通过代码完成一个10以内加减法计算器。不需要自适应，界面固定360*350。

"="按钮90*140，其它按钮90*70。

参考样式

#define DEFULT_BUTTON_STYLE "\
QPushButton{\color:#000000;\border:1px solid #AAAAAA;\border-radius:0;\background-color:#FFFFFF;\
}\
QPushButton:pressed{\color:#FFFFFF;\background-color:#AAAAAA;\
}\
"

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代码：

widget.h

#ifndef WIDGET_H
#define WIDGET_H#include <QWidget>
#include <QtWidgets>
namespace Ui {
class Widget;
}class Widget : public QWidget
{Q_OBJECTpublic:explicit Widget(QWidget *parent = nullptr);~Widget();private:Ui::Widget *ui;int num1; // 操作数1int num2; // 操作数2QString m_operator; // 运算符QString current_input1; // 操作数1QString current_input2; // 操作数2int result; // 结果int flag; // 是否已经输入运算符
};#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"
#define DEFULT_BUTTON_STYLE "\
QPushButton{\color:#000000;\border:1px solid #AAAAAA;\border-radius:0;\background-color:#FFFFFF;\
}\
QPushButton:pressed{\color:#FFFFFF;\background-color:#AAAAAA;\
}\
"Widget::Widget(QWidget *parent) :QWidget(parent),ui(new Ui::Widget)
{ui->setupUi(this);this->setWindowTitle("计算器");current_input1.clear(); // 清空字符串current_input2.clear();flag = 0; // flag置0QLabel *label = new QLabel; // 结果输出框labellabel->setAlignment(Qt::AlignRight|Qt::AlignHCenter|Qt::AlignVCenter); // 靠右居中对齐label->setText("0");label->setSizePolicy(QSizePolicy::Preferred,QSizePolicy::Preferred);QPushButton *button[10];for(int i = 0;i < 10;i++){button[i] = new QPushButton;button[i]->setText(QString::number(i));button[i]->setSizePolicy(QSizePolicy::Preferred,QSizePolicy::Preferred);button[i]->setStyleSheet("DEFULT_BUTTON_STYLE");connect(button[i],&QPushButton::clicked,this,[=](){if(flag ==0){current_input1 += QString::number(i); // 数字转换成字符串拼接label->setText(current_input1); // 显示到label上}else{current_input2 += QString::number(i); // 数字转换成字符串拼接QString temp = current_input1 + m_operator + current_input2; // 字符串拼接label->setText(temp); // 显示}});}QPushButton *add_button = new QPushButton;add_button->setText("+");add_button->setSizePolicy(QSizePolicy::Preferred,QSizePolicy::Preferred);connect(add_button,&QPushButton::clicked,this,[=](){m_operator = "+";flag = 1;QString temp = current_input1 + m_operator; // 字符串拼接label->setText(temp); // 显示});QPushButton *sub_button = new QPushButton;sub_button->setText("-");sub_button->setSizePolicy(QSizePolicy::Preferred,QSizePolicy::Preferred);connect(sub_button,&QPushButton::clicked,this,[=](){m_operator = "-";flag = 1;QString temp = current_input1 + m_operator;label->setText(temp); // 显示});QPushButton *equal_button = new QPushButton;equal_button->setText("=");equal_button->setSizePolicy(QSizePolicy::Preferred,QSizePolicy::Preferred);connect(equal_button,&QPushButton::clicked,this,[=](){num1 = current_input1.toInt();num2 = current_input2.toInt();if(m_operator == "+")result = num1 + num2;else if(m_operator == "-")result = num1 - num2;QString temp = QString("%1 %2 %3 = %4").arg(num1).arg(m_operator).arg(num2).arg(result);label->setText(temp); // 显示current_input1.clear();current_input2.clear();num1 = 0;num2 = 0;flag = 0;});QPushButton *clear_button = new QPushButton;clear_button->setText("C");clear_button->setSizePolicy(QSizePolicy::Preferred,QSizePolicy::Preferred);connect(clear_button,&QPushButton::clicked,this,[=](){current_input1.clear(); // 清空current_input2.clear();num1 = 0;num2 = 0;flag = 0;label->setText("0"); // 显示到label上});QPushButton *del_button = new QPushButton;del_button->setText("DEL");del_button->setSizePolicy(QSizePolicy::Preferred,QSizePolicy::Preferred);connect(del_button,&QPushButton::clicked,this,[=](){if(flag == 0){ // flag==0 说明目前处于第一个操作数current_input1.chop(1); // 去除尾端数字label->setText(current_input1);}else if(flag == 1 && current_input2.isEmpty()){ // 说明目前已经输入完运算符但还没有输入第二个操作数m_operator =""; // 设置为空flag = 0;label->setText(current_input1); // 显示}else{ // 说明目前处于第二个操作数current_input2.chop(1); // 去除尾端数字QString temp = current_input1 + m_operator + current_input2;label->setText(temp); // 显示}});QGridLayout *layout = new QGridLayout(this); // 网格布局layout->addWidget(label,0,0,1,4);layout->addWidget(clear_button,1,0,1,1);layout->addWidget(del_button,1,1,1,1);layout->addWidget(add_button,1,2,1,1);layout->addWidget(sub_button,1,3,1,1);layout->addWidget(button[7],2,0,1,1);layout->addWidget(button[8],2,1,1,1);layout->addWidget(button[9],2,2,1,1);layout->addWidget(button[0],2,3,1,1);layout->addWidget(button[4],3,0,1,1);layout->addWidget(button[5],3,1,1,1);layout->addWidget(button[6],3,2,1,1);layout->addWidget(button[1],4,0,1,1);layout->addWidget(button[2],4,1,1,1);layout->addWidget(button[3],4,2,1,1);layout->addWidget(equal_button,3,3,2,1);layout->setMargin(0); // 边界layout->setSpacing(0); // 各部件之间间距
}Widget::~Widget()
{delete ui;
}

main.cpp

#include "widget.h"
#include <QApplication>int main(int argc, char *argv[])
{QApplication a(argc, argv);Widget w;w.show();return a.exec();
}

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输出：

初始化界面：

示例：