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Readme.md

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+### Калькулятор с графическим интерфейсом
+
+```cpp
+#include <QApplication>
+#include <QWidget>
+#include <QGridLayout>
+#include <QLineEdit>
+#include <QPushButton>
+#include <QString>
+
+class Calculator : public QWidget {
+public:
+    Calculator() {
+        auto *layout = new QGridLayout(this);
+
+        display = new QLineEdit();
+        display->setReadOnly(true);
+        display->setAlignment(Qt::AlignRight);
+        layout->addWidget(display, 0, 0, 1, 4);
+
+        QString buttons[4][4] = {
+            {"7","8","9","/"},
+            {"4","5","6","*"},
+            {"1","2","3","-"},
+            {"C","0","=","+"}
+        };
+
+        for (int i = 0; i < 4; i++) {
+            for (int j = 0; j < 4; j++) {
+                QString text = buttons[i][j];
+                auto *btn = new QPushButton(text);
+                layout->addWidget(btn, i + 1, j);
+
+                connect(btn, &QPushButton::clicked, this, [=]() {
+                    handleInput(text);
+                });
+            }
+        }
+    }
+
+private:
+    QLineEdit *display;
+    QString current;
+
+    void handleInput(const QString &text) {
+        if (text == "C") {
+            current.clear();
+        }
+        else if (text == "=") {
+            current = QString::number(evaluate(current));
+        }
+        else {
+            current += text;
+        }
+
+        display->setText(current);
+    }
+
+    double evaluate(const QString &expr) {
+        // простой парсер: число операция число
+        QString op;
+        int pos = -1;
+
+        for (int i = 0; i < expr.size(); i++) {
+            if (QString("+-*/").contains(expr[i])) {
+                op = expr[i];
+                pos = i;
+                break;
+            }
+        }
+
+        if (pos == -1) return expr.toDouble();
+
+        double a = expr.left(pos).toDouble();
+        double b = expr.mid(pos + 1).toDouble();
+
+        if (op == "+") return a + b;
+        if (op == "-") return a - b;
+        if (op == "*") return a * b;
+        if (op == "/") return b != 0 ? a / b : 0;
+
+        return 0;
+    }
+};
+
+int main(int argc, char *argv[]) {
+    QApplication app(argc, argv);
+
+    Calculator w;
+    w.setWindowTitle("Calculator");
+    w.resize(250, 300);
+    w.show();
+
+    return app.exec();
+}
+
+```
+
+### Базовый ToDO с графическим интерфейсом
+
+```cpp
+#include <QApplication>
+#include <QWidget>
+#include <QVBoxLayout>
+#include <QHBoxLayout>
+#include <QListWidget>
+#include <QLineEdit>
+#include <QPushButton>
+#include <QFile>
+#include <QTextStream>
+#include <QDebug>
+
+class NotesApp : public QWidget {
+public:
+    NotesApp() {
+        auto *layout = new QVBoxLayout(this);
+
+        list = new QListWidget();
+        input = new QLineEdit();
+
+        auto *btnAdd = new QPushButton("Add");
+        auto *btnDel = new QPushButton("Delete");
+        auto *btnSave = new QPushButton("Save");
+
+        auto *btnLayout = new QHBoxLayout();
+        btnLayout->addWidget(btnAdd);
+        btnLayout->addWidget(btnDel);
+        btnLayout->addWidget(btnSave);
+
+        layout->addWidget(list);
+        layout->addWidget(input);
+        layout->addLayout(btnLayout);
+
+        connect(btnAdd, &QPushButton::clicked, this, &NotesApp::addNote);
+        connect(btnDel, &QPushButton::clicked, this, &NotesApp::deleteNote);
+        connect(btnSave, &QPushButton::clicked, this, &NotesApp::saveNotes);
+
+        loadNotes();
+    }
+
+private:
+    QListWidget *list;
+    QLineEdit *input;
+
+
+    QString filePath = "/home/lux/Документы/notes.txt";
+
+    void addNote() {
+        QString text = input->text().trimmed();
+        if (!text.isEmpty()) {
+            list->addItem(text);
+            input->clear();
+        }
+    }
+
+    void deleteNote() {
+        auto *item = list->currentItem();
+        if (item) delete item;
+    }
+
+    void saveNotes() {
+        QFile file(filePath);
+
+        if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
+            qDebug() << "Ошибка сохранения:" << filePath;
+            return;
+        }
+
+        QTextStream out(&file);
+
+        for (int i = 0; i < list->count(); i++) {
+            out << list->item(i)->text() << "\n";
+        }
+
+        qDebug() << "Сохранено в:" << filePath;
+    }
+
+    void loadNotes() {
+        QFile file(filePath);
+
+        if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
+            qDebug() << "Файл не найден, создаётся новый";
+            return;
+        }
+
+        QTextStream in(&file);
+
+        while (!in.atEnd()) {
+            QString line = in.readLine().trimmed();
+            if (!line.isEmpty())
+                list->addItem(line);
+        }
+
+        qDebug() << "Загружено из:" << filePath;
+    }
+};
+
+int main(int argc, char *argv[]) {
+    QApplication app(argc, argv);
+
+    NotesApp w;
+    w.setWindowTitle("Notes App");
+    w.resize(400, 300);
+    w.show();
+
+    return app.exec();
+}
+```