diff --git a/calculator.cpp b/calculator.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..c53bb289c00d7c8f9210c19b1bea922a2568159c
--- /dev/null
+++ b/calculator.cpp
@@ -0,0 +1,539 @@
+#include "calculator.h"
+#include "button.h"
+#include <math.h>
+#include <QGridLayout>
+#include <QRadioButton>
+#include<QGroupBox>
+#include<QInputDialog>
+#include <QMainWindow>
+#include <cctype>
+
+Calculator::Calculator(QWidget *parent)
+    : QMainWindow(parent)
+{
+
+    sumSoFar = 0.0;
+    factorSoFar = 0.0;
+    waitingForOperand = true;
+    setMinimumSize(380, 450);
+    setMaximumSize(380, 450);
+
+    usually= new QRadioButton("Обычный");
+    usually->setChecked(true);
+    connect(usually, SIGNAL(toggled(bool)), SLOT(SwitchMode()));
+
+    CreateSimpleCalcWidget();
+    CreateComplCalcWidget();
+    CreateDefaultCalcWidget();
+    mainWidget = new QWidget;
+    SpawnSimpleMode();
+
+    setWindowTitle(tr("Calculator"));
+}
+
+Calculator::~Calculator()
+{
+    delete usually;
+    delete display;
+    delete mainWidget;
+    delete simpleCalcLayout;
+    delete complCalcLayout;
+    delete defaultCalcLayout;
+    delete mainLayout;
+}
+
+void Calculator::digitClicked()
+{
+    Button *clickedButton = qobject_cast<Button *>(sender());
+    int digitValue = clickedButton->text().toInt();
+    if (display->text() == "0" && digitValue == 0.0)
+        return;
+
+    if (waitingForOperand) {
+        display->clear();
+        waitingForOperand = false;
+    }
+    display->setText(display->text() + QString::number(digitValue));
+}
+
+void Calculator::unaryOperatorClicked()
+{
+    Button *clickedButton = qobject_cast<Button *>(sender());
+    QString clickedOperator = clickedButton->text();
+    double operand = display->text().toDouble();
+    double result = 0.0;
+
+    if (clickedOperator == tr("\u221A")) {
+        if (operand < 0.0) {
+            abortOperation();
+            return;
+        }
+        result = sqrt(operand);
+    } else if (clickedOperator == tr("x\u00B2")) {
+        result = pow(operand, 2.0);
+    } else if (clickedOperator == tr("x\263")) {
+        result = pow(operand, 3.0);
+    } else
+        if (clickedOperator == tr("1/x")) {
+            if (operand == 0.0) {
+                abortOperation();
+                return;
+            }
+            result = 1.0 / operand;
+        }
+    display->setText(QString::number(result));
+    waitingForOperand = true;
+}
+
+void Calculator::additiveOperatorClicked()
+{
+    Button *clickedButton = qobject_cast<Button *>(sender());
+    QString clickedOperator = clickedButton->text();
+    double operand = display->text().toDouble();
+
+    if (!pendingMultiplicativeOperator.isEmpty()) {
+        if (!calculate(operand, pendingMultiplicativeOperator)) {
+            abortOperation();
+            return;
+        }
+        display->setText(QString::number(factorSoFar));
+        operand = factorSoFar;
+        factorSoFar = 0.0;
+        pendingMultiplicativeOperator.clear();
+    }
+
+    if (!pendingAdditiveOperator.isEmpty()) {
+        if (!calculate(operand, pendingAdditiveOperator)) {
+            abortOperation();
+            return;
+        }
+        display->setText(QString::number(sumSoFar));
+    } else {
+        sumSoFar = operand;
+    }
+
+    pendingAdditiveOperator = clickedOperator;
+    waitingForOperand = true;
+}
+
+void Calculator::multiplicativeOperatorClicked()
+{
+    Button *clickedButton = qobject_cast<Button *>(sender());
+    QString clickedOperator = clickedButton->text();
+    double operand = display->text().toDouble();
+
+    if (!pendingMultiplicativeOperator.isEmpty()) {
+        if (!calculate(operand, pendingMultiplicativeOperator)) {
+            abortOperation();
+            return;
+        }
+        display->setText(QString::number(factorSoFar));
+    } else {
+        factorSoFar = operand;
+    }
+
+    pendingMultiplicativeOperator = clickedOperator;
+    waitingForOperand = true;
+}
+
+void Calculator::trigonometryOperatorClicked()
+{
+    Button *clickedButton = qobject_cast<Button *>(sender());
+    QString clickedOperator = clickedButton->text();
+    double operand = display->text().toDouble();
+    double result = 0.0;
+
+    if (clickedOperator == tr("sin")) {
+        result=sin(operand);
+    }else if(clickedOperator == tr("cos"))
+    {
+        result=cos(operand);
+    }else if(clickedOperator == tr("tag"))
+    {
+        result=tan(operand);
+    }else  if (clickedOperator == tr("sinh")) {
+        result=sinh(operand);
+    }else if(clickedOperator == tr("cosh"))
+    {
+        result=cosh(operand);
+    }else if(clickedOperator == tr("tagh"))
+    {
+        result=tanh(operand);
+    }
+    waitingForOperand = true;
+    display->setText(QString::number(result));
+}
+
+void Calculator::constantOperatorClicked()
+{
+    Button *clickedButton = qobject_cast<Button *>(sender());
+    QString clickedOperator = clickedButton->text();
+    if (clickedOperator ==tr("exp")) {
+        display->setText( QString::number(exp(1)));
+    }else
+        if (clickedOperator == tr("pi")) {
+            display->setText(QString::number(M_PI));
+        }
+    waitingForOperand = true;
+}
+
+int factorial(int n) {
+    if (n < 0) {
+        return 0;
+    }
+    return !n ? 1 : n * factorial(n - 1);
+}
+
+void Calculator::unusullyClicked()
+{
+    Button *clickedButton = qobject_cast<Button *>(sender());
+    QString clickedOperator = clickedButton->text();
+    double operand = display->text().toDouble();
+    double result = 0.0;
+
+    if (clickedOperator == tr("n!")) {
+        if (operand < 0.0) {
+            abortOperation();
+            return;
+        }
+        if(operand-int(operand)!=0)
+        {
+            abortOperation();
+            return;
+        }
+        result=factorial(operand);
+    }else if (clickedOperator == tr("ln")) {
+        if (operand < 0.0) {
+            abortOperation();
+            return;
+        }
+
+        result=log(operand);
+    }else if (clickedOperator == tr("log")) {
+        if (operand < 0.0) {
+            abortOperation();
+            return;
+        }
+        result=log(operand);
+
+    }
+
+
+    display->setText(QString::number(result));
+    waitingForOperand = true;
+
+
+}
+
+void Calculator::extraunaryOperatorClicked()
+{
+    Button *clickedButton = qobject_cast<Button *>(sender());
+    QString clickedOperator = clickedButton->text();
+    double operand = display->text().toDouble();
+    double result = 0.0;
+
+    if (clickedOperator == tr("x\u00B3")) {
+        result = pow(operand, 3.0);
+    } else{
+        if (clickedOperator == tr("x\u207F n")) {
+            sqrtMemore=operand;
+            display->clear();
+        }
+    } if (clickedOperator == tr("x^0.5y")) {
+        sqrtpolMemory=operand;
+        display->clear();
+    }
+
+    display->setText(QString::number(result));
+    waitingForOperand = true;
+}
+
+
+
+void Calculator::equalClicked()
+{
+    double operand = display->text().toDouble();
+
+    if (!pendingMultiplicativeOperator.isEmpty()) {
+        if (!calculate(operand, pendingMultiplicativeOperator)) {
+            abortOperation();
+            return;
+        }
+        operand = factorSoFar;
+        factorSoFar = 0.0;
+        pendingMultiplicativeOperator.clear();
+    }
+    if (!pendingAdditiveOperator.isEmpty()) {
+        if (!calculate(operand, pendingAdditiveOperator)) {
+            abortOperation();
+            return;
+        }
+        pendingAdditiveOperator.clear();
+    } else {
+        sumSoFar = operand;
+    }
+
+    display->setText(QString::number(sumSoFar));
+    if(sqrtMemore!=1)
+    {
+        sumSoFar=pow(operand,sqrtMemore);
+        sqrtMemore=1;
+    }
+    if(sqrtpolMemory!=1)
+    {
+        sumSoFar=pow(operand, sqrtpolMemory/2);
+        sqrtpolMemory=1;
+    }
+    display->setText(QString::number(sumSoFar));
+    sumSoFar = 0.0;
+    waitingForOperand = true;
+}
+
+void Calculator::pointClicked()
+{
+    if (waitingForOperand)
+        display->setText("0");
+    if (!display->text().contains("."))
+        display->setText(display->text() + tr("."));
+    waitingForOperand = false;
+}
+
+void Calculator::changeSignClicked()
+{
+    QString text = display->text();
+    double value = text.toDouble();
+
+    if (value > 0.0) {
+        text.prepend(tr("-"));
+    } else if (value < 0.0) {
+        text.remove(0, 1);
+    }
+    display->setText(text);
+}
+
+void Calculator::backspaceClicked()
+{
+    if (waitingForOperand)
+        return;
+
+    QString text = display->text();
+    text.chop(1);
+    if (text.isEmpty()) {
+        text = "0";
+        waitingForOperand = true;
+    }
+    display->setText(text);
+}
+
+void Calculator::clear()
+{
+    if (waitingForOperand)
+        return;
+
+    display->setText("0");
+    waitingForOperand = true;
+}
+
+void Calculator::clearAll()
+{
+    sumSoFar = 0.0;
+    factorSoFar = 0.0;
+    pendingAdditiveOperator.clear();
+    pendingMultiplicativeOperator.clear();
+    display->setText("0");
+    waitingForOperand = true;
+}
+
+void Calculator::SwitchMode()
+{
+    if (!usually->isChecked()) {
+        delete mainLayout;
+        setMinimumSize(685, 450);
+        setMaximumSize(685, 450);
+        SpawnComplMode();
+    } else {
+        delete mainLayout;
+        setMinimumSize(380, 450);
+        setMaximumSize(380, 450);
+        SpawnSimpleMode();
+    }
+}
+
+void Calculator::SpawnComplMode()
+{
+    mainLayout = new QGridLayout;
+    mainLayout->setSpacing(0);
+    mainLayout->addWidget(defaultCalcWidget, 0, 0, 1, 9);
+    mainLayout->addWidget(complCalcWidget,   1, 0, 2, 4);
+    mainLayout->addWidget(simpleCalcWidget,  1, 4, 2, 5);
+    complCalcWidget->show();
+
+    mainWidget->setLayout(mainLayout);
+
+    setCentralWidget(mainWidget);
+    centralWidget()->layout()->setContentsMargins(0, 0, 0, 0);
+}
+
+void Calculator::SpawnSimpleMode()
+{
+    mainLayout = new QGridLayout;
+    mainLayout->setSpacing(0);
+    complCalcWidget->hide();
+    mainLayout->addWidget(defaultCalcWidget, 0, 0, 1, 3);
+    mainLayout->addWidget(simpleCalcWidget,  1, 0, 2, 3);
+
+    mainWidget->setLayout(mainLayout);
+    setCentralWidget(mainWidget);
+    centralWidget()->layout()->setContentsMargins(0, 0, 0, 0);
+}
+
+void Calculator::CreateSimpleCalcWidget()
+{
+
+    for (int i = 0; i < NumDigitButtons; ++i) {
+        digitButtons[i] = createButton(QString::number(i), SLOT(digitClicked()));
+    }
+
+    Button *pointButton = createButton(tr("."), SLOT(pointClicked()));
+
+    Button *divisionButton = createButton(tr("\u00F7"), SLOT(multiplicativeOperatorClicked()));//:
+    Button *timesButton = createButton(tr("\u00D7"), SLOT(multiplicativeOperatorClicked()));//*
+    Button *minusButton = createButton(tr("-"), SLOT(additiveOperatorClicked()));
+    Button *plusButton = createButton(tr("+"), SLOT(additiveOperatorClicked()));
+
+    Button *squareRootButton = createButton(tr("\u221A"), SLOT(unaryOperatorClicked()));
+    Button *reciprocalButton = createButton(tr("1/x"), SLOT(unaryOperatorClicked()));
+    Button *equalButton = createButton(tr("="), SLOT(equalClicked()));
+
+    simpleCalcLayout = new QGridLayout(this);
+    simpleCalcLayout->setSpacing(0);
+    simpleCalcLayout->setContentsMargins(0, 0, 0, 0);
+
+    for (int i = 1; i < NumDigitButtons; ++i) {
+        int row = ((9 - i) / 3) + 2;
+        int column = ((i - 1) % 3) + 1;
+        simpleCalcLayout->addWidget(digitButtons[i], row, column);
+    }
+
+    simpleCalcLayout->addWidget(digitButtons[0], 5, 1,1,2);
+    simpleCalcLayout->addWidget(pointButton, 5, 3);
+
+    simpleCalcLayout->addWidget(divisionButton, 2, 4);
+    simpleCalcLayout->addWidget(timesButton, 3, 4);
+    simpleCalcLayout->addWidget(minusButton, 4, 4);
+    simpleCalcLayout->addWidget(plusButton, 5, 4);
+
+    simpleCalcLayout->addWidget(squareRootButton, 2, 5);
+    simpleCalcLayout->addWidget(reciprocalButton, 3, 5);
+    simpleCalcLayout->addWidget(equalButton, 4, 5,2,1);
+
+    simpleCalcWidget = new QWidget(this);
+    simpleCalcWidget->setLayout(simpleCalcLayout);
+
+}
+
+void Calculator::CreateComplCalcWidget()
+{
+    Button *squareButton = createButton(tr("x\u00B2"), SLOT(unaryOperatorClicked()));//^2
+    Button *cubeButton = createButton(tr("x\u00B3"), SLOT(extraunaryOperatorClicked()));//^3
+    Button *degreeButton = createButton(tr("x\u207F"), SLOT(extraunaryOperatorClicked()));//x^y
+    Button *sqrdegreeButton = createButton(tr("x^0.5y"),SLOT(extraunaryOperatorClicked()));
+    Button *expButton = createButton(tr("exp"),  SLOT(constantOperatorClicked()));
+    Button *piButton = createButton(tr("pi"),  SLOT(constantOperatorClicked()));
+    Button *lnButton = createButton(tr("ln"),  SLOT(unusullyClicked()));
+    Button *logButton = createButton(tr("log"),  SLOT(digitClicked()));
+    Button *cubesqlButton = createButton(tr("\u00B3\u221A"),  SLOT(multiplicativeOperatorClicked()));
+    Button *sinButton = createButton(tr("sin"),  SLOT(trigonometryOperatorClicked()));
+    Button *cosButton = createButton(tr("cos"),  SLOT(trigonometryOperatorClicked()));
+    Button *tanButton = createButton(tr("tan"),  SLOT(trigonometryOperatorClicked()));
+    Button *sinhButton = createButton(tr("sinh"),  SLOT(trigonometryOperatorClicked()));
+    Button *coshButton = createButton(tr("cosh"),  SLOT(trigonometryOperatorClicked()));
+    Button *tanhButton = createButton(tr("tanh"),  SLOT(trigonometryOperatorClicked()));
+    Button *factButton = createButton(tr("n!"),  SLOT(unusullyClicked()));
+
+
+    complCalcLayout = new QGridLayout(this);
+    complCalcLayout->setSpacing(0);
+    complCalcLayout->setContentsMargins(0, 0, 0, 0);
+
+    complCalcLayout->addWidget(sinhButton, 2, 0);
+    complCalcLayout->addWidget(coshButton, 3, 0);
+    complCalcLayout->addWidget(tanhButton, 4, 0);
+    complCalcLayout->addWidget(factButton, 5, 0);
+    complCalcLayout->addWidget(sinButton, 2, 1);
+    complCalcLayout->addWidget(cosButton, 3, 1);
+    complCalcLayout->addWidget(tanButton, 4, 1);
+    complCalcLayout->addWidget(piButton, 5, 1);
+    complCalcLayout->addWidget(expButton, 2, 2);
+    complCalcLayout->addWidget(lnButton, 3, 2);
+    complCalcLayout->addWidget(logButton, 4, 2);
+    complCalcLayout->addWidget(cubesqlButton, 5, 2);
+    complCalcLayout->addWidget(squareButton, 2, 3);
+    complCalcLayout->addWidget(cubeButton, 3, 3);
+    complCalcLayout->addWidget(degreeButton, 4, 3);
+    complCalcLayout->addWidget(sqrdegreeButton, 5, 3);
+
+    complCalcWidget = new QWidget(this);
+    complCalcWidget->setLayout(complCalcLayout);
+}
+
+void Calculator::CreateDefaultCalcWidget()
+{
+    Button *clearButton = createButton(tr("C"), SLOT(clearAll()));
+    display = new QLineEdit("0");
+    display->setReadOnly(true);
+    display->setAlignment(Qt::AlignRight);
+    display->setMaxLength(15);
+
+
+    QFont font = display->font();
+    font.setPointSize(font.pointSize() + 10);
+    display->setFont(font);
+
+    QRadioButton * ingener= new QRadioButton("Инженерный");
+
+    defaultCalcLayout = new QGridLayout(this);
+    defaultCalcLayout->setSpacing(0);
+    defaultCalcLayout->setContentsMargins(0, 0, 0, 0);
+
+    defaultCalcLayout->addWidget(display,  0, 0, 2, 5);
+    defaultCalcLayout->addWidget(clearButton,   2, 4, 2, 1);
+    defaultCalcLayout->addWidget(ingener,3, 0, 1, 3);
+    defaultCalcLayout->addWidget(usually,2, 0, 1, 3);
+
+
+    defaultCalcWidget = new QWidget(this);
+    defaultCalcWidget->setLayout(defaultCalcLayout);
+
+
+}
+
+
+Button *Calculator::createButton(const QString &text, const char *member)
+{
+    Button *button = new Button(text);
+    connect(button, SIGNAL(clicked()), this, member);
+    return button;
+}
+
+void Calculator::abortOperation()
+{
+    clearAll();
+    display->setText(tr("####"));
+}
+
+bool Calculator::calculate(double rightOperand, const QString &pendingOperator)
+{
+    if (pendingOperator == tr("+")) {
+        sumSoFar += rightOperand;
+    } else if (pendingOperator == tr("-")) {
+        sumSoFar -= rightOperand;
+    } else if (pendingOperator == tr("\u00D7")) {
+        factorSoFar *= rightOperand;
+    } else if (pendingOperator == tr("\u00F7")) {
+        if (rightOperand == 0.0)
+            return false;
+        factorSoFar /= rightOperand;
+    }
+    return true;
+}