实现简易计算器 网格布局 QT环境 纯代码C++实现

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;\
}\
"

代码：

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QtWidgets>
namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = nullptr);
    ~Widget();

private:
    Ui::Widget *ui;
    int num1; // 操作数1
    int num2; // 操作数2
    QString m_operator; // 运算符
    QString current_input1; // 操作数1
    QString current_input2; // 操作数2
    int 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);

    current_input1.clear(); // 清空字符串
    current_input2.clear();
    flag = 0; // flag置0

    QLabel *label = new QLabel; // 结果输出框label
    label->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();
}

输出：

初始化界面：

示例：