Qt creator实现一个简单计算器

目录

1 界面设计

2 思路简介

3 代码

目录

1 界面设计

​2 思路简介

3 代码

3.1 widget.h

3.2 widget.c

4 完整代码

        在这里主要记载了如何使用Qt creator完成一个计算器的功能。该计算器可以实现正常的加减乘除以及括号操作，能实现简单的计算器功能。

1 界面设计

该计算器的界面设计如下所示：

2 思路简介

        1. 中缀表达式的构建

        将按键输入字符转换为字符串的形式。

        比如：中缀表达式3+2+34+(6-3*5);

        那么可以定义一个字符数组char Chars[1024];存储，之后使用QString::fromUtf8(this->Chars);将该字符数组转换为LineEdit可以显示的类型。

        2. 中缀表达式转变为后缀表达式

        直接按照字符将中缀转变为后缀表达式，在进行计算时，再转换为数据和符号。这里在将中缀表达式转变为后缀表达式时，把每个数都使用&进行分割，方便后续计算。比如32+21转换为后缀表达式就是32&&21+。

        3. 使用后缀表达式进行计算

3 代码

3.1 widget.h

#ifndef WIDGET_H
#define WIDGET_H
 
#include 
 
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE
 
class Widget : public QWidget
{
    Q_OBJECT
 
public:
    Widget(QWidget *parent = nullptr);
    ~Widget();
    void Fb_Change(); // 中缀转换为后缀表达式
    void Clear();
public:
    int i,j;
 
private slots:
    void on_but_one_clicked();
 
    void on_but_zero_clicked();
 
    void on_but_two_clicked();
 
    void on_but_three_clicked();
 
    void on_but_four_clicked();
 
    void on_but_five_clicked();
 
    void on_but_six_clicked();
 
    void on_but_seven_clicked();
 
    void on_but_eight_clicked();
 
    void on_but_nine_clicked();
 
    void on_but_add_clicked();
 
    void on_but_sub_clicked();
 
    void on_but_mul_clicked();
 
    void on_but_div_clicked();
 
    void on_but_leftbrk_clicked();
 
    void on_but_rightbrk_clicked();
 
    void on_but_cls_clicked();
 
    void on_but_bit_clicked();
 
    void on_but_eql_clicked();
 
    void on_but_close_clicked();
 
private:
    Ui::Widget *ui;
    int Data[128];    // data stack
    char suffix[128];  //  后缀表达式 stack
    char sign[128];     // 符号栈
    char Chars[1024]; // zhong缀表达式字符数组
    int data_sp = 0;  // 数据栈顶指针
    int suffix_sp = 0;  // 后缀栈顶指针
    int sign_sp = 0;    // 符号栈顶指针
    int char_sp = 0;  //
    int Operation_end = 0;  // 运算结束标志位,1:运算结束
};
#endif // WIDGET_H

3.2 widget.c

#include "widget.h"
#include "ui_widget.h"
#include "qdebug.h"
 
Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
}
 
Widget::~Widget()
{
    delete ui;
}
 
 
void Widget::on_but_one_clicked()
{
    this->Chars[char_sp++] = '1';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_zero_clicked()
{
    this->Chars[char_sp++] = '0';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_two_clicked()
{
    this->Chars[char_sp++] = '2';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_three_clicked()
{
    this->Chars[char_sp++] = '3';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_four_clicked()
{
    this->Chars[char_sp++] = '4';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_five_clicked()
{
    this->Chars[char_sp++] = '5';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_six_clicked()
{
    this->Chars[char_sp++] = '6';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_seven_clicked()
{
    this->Chars[char_sp++] = '7';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_eight_clicked()
{
    this->Chars[char_sp++] = '8';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_nine_clicked()
{
    this->Chars[char_sp++] = '9';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_add_clicked()
{
    this->Chars[char_sp++] = '+';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_sub_clicked()
{
    this->Chars[char_sp++] = '-';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_mul_clicked()
{
    this->Chars[char_sp++] = '*';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_div_clicked()
{
    this->Chars[char_sp++] = '/';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_leftbrk_clicked()
{
    this->Chars[char_sp++] = '(';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_rightbrk_clicked()
{
    this->Chars[char_sp++] = ')';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars));
}
 
void Widget::on_but_cls_clicked()
{
    Clear();
}
 
void Widget::on_but_bit_clicked()
{
    if(Operation_end == 0)   // 没有运算结束
    {
        this->Chars[--char_sp] = ' ';
        Chars[char_sp] ='\0';
        ui->lineEdit->setText(QString::fromUtf8(this->Chars));
    }else {
    // 运算结束
    Clear();
    }
}
 
void Widget::on_but_eql_clicked()
{
    Fb_Change();
}
void Widget::Clear()
{
    this->char_sp = 0;
    ui->lineEdit->clear();
    for(i=0; i
    {
        this->sign[i] = ' ';
    }
    sign[0] ='\0';
    this->sign_sp = 0;
    for(i=0; i
    {
        this->suffix[i] = ' ';
    }
    this->suffix_sp = 0;
    suffix[0] ='\0';
 
    for(i=0; i
    {
        this->Data[i] = 0;
    }
    this->data_sp = 0;
    Operation_end = 0;  // 运算结束标志位
}
 
// 中缀转换为后缀表达式
void Widget::Fb_Change()
{
    int font=0;
    int flag = 0;
    i = char_sp;
    j = 0;
    int count = 0;
 
    // 12*4+34/5-(56=67*4)+32 => 12 4 * 34 5 / 56 67 4 * + - 32 + +
 
    qDebug() << "1";
    while(i--)      // 总共字符个数
    {
       if(isdigit(this->Chars[j]))  // 如果是数字字符
       {
            if(flag == 0)
            {
                suffix[suffix_sp++] = this->Chars[j];  // !
                j++;
            }else{
                suffix[suffix_sp++] = '&';  //  主要是为了正确分割数据, 和flag配合
                suffix[suffix_sp++] = this->Chars[j];  // !
                j++;
                flag = 0;
            }
 
            continue;
       }
       if((sign_sp == 0 || sign[sign_sp-1] == '(') && this->Chars[j] != ')')  // 如果符hao栈为空或者栈顶元素为'('
       {
            qDebug() << "null" <
            suffix[suffix_sp++] = '&'; // 主要是为了正确分割数据, 和flag配合
            sign[sign_sp++] = this->Chars[j];  // !
            j++;
            flag = 1;  // 主要是为了正确分割数据
            continue;
       }
       //
       if((this->Chars[j] == '*' || this->Chars[j] == '/') && (sign[sign_sp-1] == '-' || sign[sign_sp-1] == '+'))
       {
           sign[sign_sp++] = this->Chars[j];  // !
           j++;
           flag = 1;  //
           continue;
       }
       if((this->Chars[j] == '*' || this->Chars[j] == '/') && (sign[sign_sp-1] == '*' || sign[sign_sp-1] == '/'))
       {
           suffix[suffix_sp++] = '&'; // 主要是为了正确分割数据, 和flag配合
           suffix[suffix_sp++] = sign[--sign_sp];
           sign[sign_sp++] = this->Chars[j];
           j++;
           flag = 1;  // 主要是为了正确分割数据
           continue;
       }
       if(this->Chars[j] == '+' || this->Chars[j] == '-')
       {
           suffix[suffix_sp++] = '&'; // 主要是为了正确分割数据, 和flag配合
           suffix[suffix_sp++] = sign[--sign_sp];
           sign[sign_sp++] = this->Chars[j];
           j++;
           flag = 1;  //
           continue;
       }
       if(this->Chars[j] == '(')
       {
           sign[sign_sp++] = this->Chars[j];  // !
           j++;
           flag = 1;  //
           continue;
       }
       if(this->Chars[j] == ')')
       {
           while(sign[--sign_sp] != '(')
           {
               suffix[suffix_sp++] = '&'; // 主要是为了正确分割数据, 和flag配合
               suffix[suffix_sp++] = sign[sign_sp];
           }
           sign[sign_sp] = ' ';
           j++;
           flag = 1;  //
           continue;
       }
    }
    while(sign_sp--){
        suffix[suffix_sp++] = sign[sign_sp];
    }
    suffix[suffix_sp] = '\0';
    qDebug()<<  suffix;
 
 
    // suffix compute
    int arg_01, arg_02;
    for(i=0; i < suffix_sp; i++)
    {
        if(suffix[i] >= '0' && suffix[i] <= '9')
        {
            font = font*count*10 + ((int)suffix[i] - 48); // 252
            count = 1;
            continue;
        }
        if(suffix[i] == '&')
        {
            if(count == 1)  // 说明取过数
            {
                Data[data_sp++] = font;
                font = 0;
            }
            count = 0;
            continue;
        }
        if(suffix[i] == '+')
        {
            if(count == 1)  // 说明取过数
            {
                Data[data_sp++] = font;
                font = 0;
            }
            arg_01 = Data[--data_sp];  //
            arg_02 = Data[--data_sp];  //
            Data[data_sp++] =  arg_01+arg_02;
            qDebug() << Data[data_sp - 1];
            count = 0;
            continue;
        }
        if(suffix[i] == '-')
        {
            if(count == 1)  // 说明取过数
            {
                Data[data_sp++] = font;
                font = 0;
            }
            arg_01 = Data[--data_sp];  //
            arg_02 = Data[--data_sp];  //
            Data[data_sp++] =  arg_02 - arg_01;
 
            count = 0;
            continue;
        }
        if(suffix[i] == '*')
        {
            if(count == 1)  // 说明取过数
            {
                Data[data_sp++] = font;
                font = 0;
            }
            arg_01 = Data[--data_sp];  //
            arg_02 = Data[--data_sp];  //
            Data[data_sp++] =  arg_01 * arg_02;
 
            count = 0;
            continue;
        }
        if(suffix[i] == '/')
        {
            if(count == 1)  // 说明取过数
            {
                Data[data_sp++] = font;
                font = 0;
            }
            arg_01 = Data[--data_sp];  //
            arg_02 = Data[--data_sp];  //
            Data[data_sp++] =  arg_02 / arg_01;
 
            count = 0;
            continue;
        }
    }
    qDebug() << Data[0];
    ui->lineEdit->clear();
    this->Chars[char_sp++] = '=';
    Chars[char_sp] ='\0';
    ui->lineEdit->setText(QString::fromUtf8(this->Chars)+QString::number(Data[0]));
    Operation_end = 1;  // 运算结束标志位
 
 
}
// 237 238 236
 
void Widget::on_but_close_clicked()
{
    this->close();   // close window
}

4 完整代码

https://download.csdn.net/download/qq_51458770/89492760