Qt(C++)实现的简易计算器
软件工程的作业，让写一个计算器，为此花两天抽时间看了看Qt入门，然后就开搞了。
环境Qt 5.13.1，MinGw 7.3.0 32-bit，IDE：Qt Creator 4.10.0
新建Qt Widgets 应用，项目名称Calculator，基类选择GWidget，类名MyWidget。
1.首先是页面，直接拖拖拖，没用栅格，先垂直在水平布局了，改了一点参数，解决问题。
2.编写信号和槽，并代码实现计算器功能
mywidget.h 最终更改如下：
#ifndef MYWIDGET_H
#define MYWIDGET_H
#include
#include
#include
#include
QT_BEGIN_NAMESPACE
namespace Ui { class MyWidget; }
QT_END_NAMESPACE
class QErrorMessage;
class MyWidget : public QWidget
{
Q_OBJECT
public:
MyWidget(QWidget *parent = nullptr);
~MyWidget();
private slots:
void on_pushButtonCe_clicked();
void on_pushButtonC_clicked();
void on_pushButtonDe_clicked();
void on_pushButtonChu_clicked();
void on_pushButton7_clicked();
void on_pushButton8_clicked();
void on_pushButton9_clicked();
void on_pushButtonChen_clicked();
void on_pushButton4_clicked();
void on_pushButton5_clicked();
void on_pushButton6_clicked();
void on_pushButtonJian_clicked();
void on_pushButton1_clicked();
void on_pushButton2_clicked();
void on_pushButton3_clicked();
void on_pushButtonJia_clicked();
void on_pushButtonHuan_clicked();
void on_pushButton0_clicked();
void on_pushButtonDian_clicked();
void on_pushButtonDenyu_clicked();
void AddNum(int i);
void ShowNum();
void Operator(int i);
void TwiceOperator();
double OpreatorTrue();
void DToStr(double c);
private:
Ui::MyWidget *ui;
QErrorMessage * errordlg;
char showstr[100];
double a = 0, b = 0;
int cha = 0, wei = 10, showlen=0, oper;
bool sign = false, signdian = false, starta = false, startb = false, signa = true, signb = true;
};
#endif // MYWIDGET_H
mywidget.cpp 最终更改如下：
#include "mywidget.h"
#include "ui_mywidget.h"
#include
#include
#include
#include
const double lin = 0.0000000001;
MyWidget::MyWidget(QWidget *parent)
: QWidget(parent)
, ui(new Ui::MyWidget)
{
ui->setupUi(this);
errordlg = new QErrorMessage(this);
}
MyWidget::~MyWidget()
{
delete ui;
}
void MyWidget::DToStr(double c){
sprintf(showstr, "%.8lf", c);
showstr[8] = '\0';
showlen = 8;
for(int i=showlen-1; i>0; i--){
if(showstr[i] == '0'){
showstr[i] = '\0';
showlen--;
}else if(showstr[i] == '.'){
showstr[i] = '\0';
showlen--;
break;
}else{
break;
}
}
}
void MyWidget::ShowNum(){
qDebug() << showstr;
if(showlen == 0){
ui->lcdNumber->display(0);
}else{
ui->lcdNumber->display(showstr);
}
}
void MyWidget::AddNum(int i){
showstr[showlen++] = char(48+i);
showstr[showlen] = '\0';
if((signdian && showlen == 10) || (!signdian && showlen == 9)){
errordlg->setWindowTitle(tr("错误提示"));
errordlg->showMessage(tr("输入超限"));
showstr[--showlen] = '\0';
return;
}
cha = i;
if(!sign){
if(!starta){
showstr[0] = char(48+i);
showstr[1] = '\0';
showlen = 1;
starta = true;
}
if(signdian){
a = a + double(i) / wei;
wei *= 10;
}else{
a = a * 10 + i;
}
}else{
if(!startb){
showstr[0] = char(48+i);
showstr[1] = '\0';
showlen = 1;
startb = true;
}
if(signdian){
b = b + double(i) / wei;
wei *= 10;
}else{
b = b * 10 + i;
}
}
ShowNum();
}
void MyWidget::on_pushButtonCe_clicked()
{
if(sign){
TwiceOperator();
b = 0;
wei = 10;
signdian = false;
startb = false;
DToStr(b);
ShowNum();
}else{
a = 0;
wei = 10;
signdian = false;
starta = false;
DToStr(a);
ShowNum();
}
}
void MyWidget::on_pushButtonC_clicked()
{
a = 0; b = 0;
cha = 0; wei = 10; showlen=0; oper=0;
showstr[0] = '\0';
sign = false; signdian = false; starta = false; startb = false; signa = true; signb = true;
DToStr(0.0);
ShowNum();
}
void MyWidget::on_pushButtonDe_clicked()
{
if(!sign){
if(signdian){
a = a * wei / 10;
a -= cha;
a /= wei;
wei /= 10;
if(wei == 1){
signdian = false;
wei = 10;
//showstr[--showlen] = '\0';
}
}else{
a -= cha;
a /= 10;
cha = int(a) % 10;
}
}else{
if(signdian){
b = b * wei;
b -= cha;
cha = (int(b) % 100) / 10;
b /= wei;
wei /= 10;
if(wei == 1){
signdian = false;
wei = 10;
}
}else{
b -= cha;
b /= 10;
cha = int(b) % 10;
}
}
if(showlen>0){
showstr[--showlen] = '\0';
}
ShowNum();
}
double MyWidget::OpreatorTrue(){
switch (oper) {
case 1 : return a + b;
case 2 : return a - b;
case 3 : return a * b;
case 4 : {
if(b>=-lin && b<=lin){
errordlg->setWindowTitle(tr("错误提示"));
errordlg->showMessage(tr("除数不能为0"));
return a;
} return a / b;
}
}
return a;
}
void MyWidget::TwiceOperator(){
b = 0;
signb = true;
signa = true;
starta = true;
startb = false;
wei = 10;
showlen=0;
showstr[0] = '\0';
signdian = false;
}
void MyWidget::Operator(int i){
switch(i){
case 1:{
if(sign){
if(!signa) a = 0 - a;
if(!signb) b = 0 - b;
a = OpreatorTrue();
TwiceOperator();
oper = 1;
DToStr(a);
ShowNum();
}else{
if(!signa) a = 0 - a;
oper = 1;
sign = true;
TwiceOperator();
}
} break;
case 2:{
if(sign){
if(!startb){
startb = true;
signb = false;
showstr[0] = '-';
showstr[++showlen] = '\0';
ShowNum();
}else{
if(!signa) a = 0 - a;
if(!signb) b = 0 - b;
a = OpreatorTrue();
TwiceOperator();
oper = 2;
DToStr(a);
ShowNum();
}
}else{
if(!starta){
starta = true;
signa = false;
showstr[0] = '-';
showstr[++showlen] = '\0';
ShowNum();
}else{
if(!signa) a = 0 - a;
oper = 2;
TwiceOperator();
sign = true;
}
}
} break;
case 3:{
if(sign){
if(!signa) a = 0 - a;
if(!signb) b = 0 - b;
a = OpreatorTrue();
TwiceOperator();
oper = 3;
DToStr(a);
ShowNum();
}else{
if(!signa) a = 0 - a;
oper = 3;
TwiceOperator();
sign = true;
}
} break;
case 4:{
if(sign){
if(!signa) a = 0 - a;
if(!signb) b = 0 - b;
a = OpreatorTrue();
TwiceOperator();
oper = 4;
DToStr(a);
ShowNum();
}else{
if(!signa) a = 0 - a;
oper = 4;
TwiceOperator();
sign = true;
}
} break;
}
}
void MyWidget::on_pushButtonHuan_clicked()
{
if(sign){
if(startb){
if(signb){
signb = false;
for(int i=(++showlen); i>0; i--){
showstr[i] = showstr[i-1];
}
showstr[0] = '-';
ShowNum();
}else{
signb = true;
for(int i=0; i0; i--){
showstr[i] = showstr[i-1];
}
showstr[0] = '-';
ShowNum();
}else{
signa = true;
for(int i=0; i 3.到这就没啥了，改一下项目文件啥的换个图标
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
CONFIG += c++11
# The following define makes your compiler emit warnings if you use
# any Qt feature that has been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
# You can also make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
SOURCES += \
main.cpp \
mywidget.cpp
HEADERS += \
mywidget.h
FORMS += \
mywidget.ui
# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target
RC_ICONS = Calculator.ico
TARGET = Calculator
TEMPLATE = app
最后放效果图
最后附上所有文件的资源链接：https://download.csdn.net/download/alfa_jin/11790101