//HEADER #ifndef MAINWINDOW_H #define MAINWINDOW_H #include #include #include namespace Ui { class MainWindow; } class MainWindow : public QMainWindow { Q_OBJECT public: explicit MainWindow(QWidget *parent = 0); ~MainWindow(); signals: void numberDisplay(int digit); private slots: void digitSelect(); void operationSelect(); void totalCalc(); void setGrid(); private: QLabel *label; QLineEdit *line; QPushButton *operationButton[6]; QPushButton *numberButton[10]; }; #endif // MAINWINDOW_H //CPP #include "mainwindow.h" #include QString value{""}, total{""}; int firstValue, secondValue; bool addState{false}, minusState{false}, multiplyState{false}, divisionState{false}; MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) { this->setWindowTitle("Basic Calculator"); this->setStyleSheet("background-color: teal"); label = new QLabel("0", this); label->setGeometry(QRect(QPoint(50,75), QSize(50,200))); label->setFixedSize(200,50); label->setAlignment(Qt::AlignRight | Qt::AlignBottom); label->setStyleSheet("background-color: white"); QFont font = label->font(); font.setPointSize(18); font.setBold(true); label->setFont(font); for(int i{0}; i < 6; ++i) { QString operation[] = {"C","=","+","-","x","÷"}; operationButton[i] = new QPushButton(operation[i], this); if(i == 1) { connect(operationButton[i], SIGNAL(released()), this, SLOT(totalCalc())); } else { connect(operationButton[i], SIGNAL(released()), this, SLOT(operationSelect())); } } for(int i{0}; i < 10; ++i) { QString digit = QString::number(i); numberButton[i] = new QPushButton(digit, this); connect(numberButton[i], SIGNAL(released()), this, SLOT(digitSelect())); } setGrid(); } void MainWindow::digitSelect() { QPushButton *button = (QPushButton*)sender(); emit numberDisplay(button->text()[0].digitValue()); value += QString::number(button->text()[0].digitValue()); label->setText(value); } void MainWindow::operationSelect() { QPushButton *button = (QPushButton*)sender(); firstValue = value.toInt(); if(button->text()== "C") { value = ""; firstValue = 0; secondValue = 0; } else if(button->text()== "+") { addState = true; } else if(button->text()== "-") { minusState = true; } else if(button->text()== "x") { multiplyState = true; } else if(button->text()== "÷") { divisionState = true; } value = ""; label->setText(value); } void MainWindow::setGrid() { for(int i {0}; i < 1; ++i) { numberButton[i]->setGeometry(QRect(QPoint(50,300), QSize(50,50))); operationButton[i]->setGeometry(QRect(QPoint(100,300), QSize(50,50))); operationButton[i + 1]->setGeometry(QRect(QPoint(150,300), QSize(50,50))); operationButton[i + 2]->setGeometry(QRect(QPoint(200,300), QSize(50,50))); } for(int i {1}; i < 4; ++i) { numberButton[i]->setGeometry(QRect(QPoint(50 * i,250), QSize(50,50))); if(i == 3) { operationButton[i]->setGeometry(QRect(QPoint(200,250), QSize(50,50))); } } for(int i {4}; i < 7; ++i) { numberButton[i]->setGeometry(QRect(QPoint(50 * (i - 3),200), QSize(50,50))); if(i == 4) { operationButton[i]->setGeometry(QRect(QPoint(200,200), QSize(50,50))); } } for(int i {7}; i < 10; ++i) { numberButton[i]->setGeometry(QRect(QPoint(50 * (i - 6),150), QSize(50,50))); if(i == 7) { operationButton[i - 2]->setGeometry(QRect(QPoint(200,150), QSize(50,50))); } } } void MainWindow::totalCalc() { secondValue = value.toInt(); if(addState) { total = QString::number(firstValue + secondValue); label->setText(total); addState = false; } else if(minusState) { total = QString::number(firstValue - secondValue); label->setText(total); minusState = false; } else if(multiplyState) { total = QString::number(firstValue * secondValue); label->setText(total); multiplyState = false; } else if(divisionState) { total = QString::number(firstValue / secondValue); label->setText(total); divisionState = false; } firstValue = 0; secondValue = 0; value = ""; total = ""; } MainWindow::~MainWindow() { } //MAIN #include "mainwindow.h" #include #include int main(int argc, char *argv[]) { QApplication BasicCalculator(argc, argv); MainWindow window; window.showMaximized(); window.setFixedSize(300,400); window.move(QApplication::desktop()->screen()->rect().center() - window.rect().center()); window.show(); return BasicCalculator.exec(); }

GUI Basic Calculator Qt creator