四则运算计算器c++ qt

### C++ GUI 四则运算计算器示例 #### 使用 Qt 创建四则运算计算器 为了创建一个带有图形用户界面的四则运算计算器，可以利用Qt框架来简化开发过程。Qt是一个跨平台的应用开发框架，支持多种操作系统并提供丰富的GUI组件。 以下是基于Qt的一个简单的四则运算计算器实例： ```cpp #include <QApplication> #include <QWidget> #include <QPushButton> #include <QLineEdit> #include <QVBoxLayout> class Calculator : public QWidget { public: Calculator(QWidget *parent = nullptr); private slots: void onButtonClicked(); private: QLineEdit* display; }; Calculator::Calculator(QWidget *parent) : QWidget(parent), display(new QLineEdit(this)) { QVBoxLayout *layout = new QVBoxLayout; layout->addWidget(display); const QStringList numbers{"7", "8", "9", "4", "5", "6", "1", "2", "3", "0"}; QGridLayout *gridLayout = new QGridLayout; int row = 0, col = 0; for (const QString &text : qAsConst(numbers)){ QPushButton *button = new QPushButton(text, this); gridLayout->addWidget(button, row / 3, col % 3); connect(button, SIGNAL(clicked()), SLOT(onButtonClicked())); ++col; if(col%3==0){ ++row; } } // Add operation buttons QPushButton *additionBtn = new QPushButton("+"); QPushButton *subtractionBtn = new QPushButton("-"); QPushButton *multiplicationBtn = new QPushButton("*"); QPushButton *divisionBtn = new QPushButton("/"); QPushButton *equalBtn = new QPushButton("="); QPushButton *clearBtn = new QPushButton("C"); gridLayout->addWidget(additionBtn, 3, 3); gridLayout->addWidget(subtractionBtn, 2, 3); gridLayout->addWidget(multiplicationBtn, 1, 3); gridLayout->addWidget(divisionBtn, 0, 3); gridLayout->addWidget(equalBtn, 4, 2); gridLayout->addWidget(clearBtn, 4, 0); connect(additionBtn, SIGNAL(clicked()), SLOT(onButtonClicked())); connect(subtractionBtn, SIGNAL(clicked()), SLOT(onButtonClicked())); connect(multiplicationBtn, SIGNAL(clicked()), SLOT(onButtonClicked())); connect(divisionBtn, SIGNAL(clicked()), SLOT(onButtonClicked())); connect(equalBtn, SIGNAL(clicked()), SLOT(onButtonClicked())); connect(clearBtn, SIGNAL(clicked()), SLOT(onButtonClicked())); layout->addLayout(gridLayout); setLayout(layout); } void Calculator::onButtonClicked(){ QPushButton *clickedButton = static_cast<QPushButton*>(sender()); QString buttonText = clickedButton->text(); double allNumbers; double numBuffer=display->text().toDouble(); if (buttonText == "=") { try{ // Here you would implement the logic to evaluate expressions. // For simplicity we just clear and show a message here. display->setText("Result should be calculated here."); } catch(...){ display->setText("Error occurred during calculation."); } } else if (buttonText == "C") { display->setText(""); } else { display->setText(display->text() + buttonText); } } int main(int argc, char **argv) { QApplication app(argc, argv); Calculator calc; calc.setWindowTitle("Simple Calculator with Qt"); calc.resize(200, 300); calc.show(); return app.exec(); } ``` 这段代码展示了如何设置基本布局以及按钮点击事件处理器[^1]。需要注意的是，在实际应用中应当实现`=`按键的功能以完成表达式的求解；这里仅作为演示目的省略了具体算法实现部分。