解释C++代码:#define STRINGFY(x) #x #define TOSTRING(x) STRINGFY(x)
时间: 2024-04-11 17:18:08 浏览: 10
这段代码是 C++ 中的宏定义。它定义了两个宏:
1. `STRINGFY(x)` 宏将参数 `x` 转换为字符串常量,即将 `x` 变成一个以双引号括起来的字符串。例如,如果 `x` 是 `hello`,那么 `STRINGFY(x)` 将会被转换成 `"hello"`。
2. `TOSTRING(x)` 宏则调用了 `STRINGFY(x)` 宏,将参数 `x` 转换为字符串常量。例如,如果 `x` 是 `world`,那么 `TOSTRING(x)` 将会被转换成 `"world"`。
这两个宏可以用于在代码中将变量名转换为字符串,或者将代码中的一部分转换为字符串常量。
相关问题
c#.net在一个richtextbox中用listbox实现c++代码自动提示
实现 C++ 代码自动提示的方式与实现 C# 代码自动提示的方式类似。以下是一个简单的示例代码,可以实现在 RichTextBox 中输入 C++ 代码时,根据当前光标所在行的文本自动提示相关的 C++ 关键字和标识符:
```
private void richTextBox1_TextChanged(object sender, EventArgs e)
{
// 获取当前光标所在行的文本
int index = richTextBox1.SelectionStart;
int line = richTextBox1.GetLineFromCharIndex(index);
string text = richTextBox1.Lines[line];
// 根据文本获取匹配的代码提示列表
List<string> suggestions = GetSuggestions(text);
// 清空 ListBox,并添加提示项
listBox1.Items.Clear();
listBox1.Items.AddRange(suggestions.ToArray());
// 显示 ListBox
if (suggestions.Count > 0)
{
listBox1.Visible = true;
listBox1.Width = richTextBox1.Width;
listBox1.Top = richTextBox1.Top + (line + 1) * richTextBox1.Font.Height;
listBox1.Left = richTextBox1.Left;
}
else
{
listBox1.Visible = false;
}
}
private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
// 将选中的提示项插入到 RichTextBox 中
int index = richTextBox1.SelectionStart;
int line = richTextBox1.GetLineFromCharIndex(index);
int start = richTextBox1.GetFirstCharIndexFromLine(line);
int length = index - start;
string suggestion = listBox1.SelectedItem.ToString();
richTextBox1.SelectionStart = start;
richTextBox1.SelectionLength = length;
richTextBox1.SelectedText = suggestion;
listBox1.Visible = false;
}
private List<string> GetSuggestions(string text)
{
// 根据文本获取匹配的代码提示列表
List<string> suggestions = new List<string>();
if (text.StartsWith("#"))
{
// C++ 预处理指令
suggestions.Add("#define");
suggestions.Add("#include");
suggestions.Add("#ifdef");
suggestions.Add("#ifndef");
suggestions.Add("#endif");
}
else if (text.EndsWith("."))
{
// C++ 命名空间
suggestions.Add("std");
}
else
{
// C++ 关键字和标识符
suggestions.Add("auto");
suggestions.Add("break");
suggestions.Add("case");
suggestions.Add("char");
suggestions.Add("class");
suggestions.Add("const");
suggestions.Add("continue");
suggestions.Add("default");
suggestions.Add("delete");
suggestions.Add("do");
suggestions.Add("double");
suggestions.Add("else");
suggestions.Add("enum");
suggestions.Add("extern");
suggestions.Add("float");
suggestions.Add("for");
suggestions.Add("friend");
suggestions.Add("goto");
suggestions.Add("if");
suggestions.Add("inline");
suggestions.Add("int");
suggestions.Add("long");
suggestions.Add("mutable");
suggestions.Add("namespace");
suggestions.Add("new");
suggestions.Add("operator");
suggestions.Add("private");
suggestions.Add("protected");
suggestions.Add("public");
suggestions.Add("register");
suggestions.Add("return");
suggestions.Add("short");
suggestions.Add("signed");
suggestions.Add("sizeof");
suggestions.Add("static");
suggestions.Add("struct");
suggestions.Add("switch");
suggestions.Add("template");
suggestions.Add("this");
suggestions.Add("throw");
suggestions.Add("try");
suggestions.Add("typedef");
suggestions.Add("typeid");
suggestions.Add("typename");
suggestions.Add("union");
suggestions.Add("unsigned");
suggestions.Add("using");
suggestions.Add("virtual");
suggestions.Add("void");
suggestions.Add("volatile");
suggestions.Add("wchar_t");
suggestions.Add("while");
}
return suggestions;
}
```
需要注意的是,上述示例只是为了演示实现 C++ 代码自动提示的思路,实际应用中需要根据 C++ 语法规则和标准库的使用情况来生成代码提示列表。
基于QAbstractTableModel 实现自定义model ,实现数据的增加,删除,修改并更新表格 C++代码
以下是一个基于QAbstractTableModel的自定义model的示例代码,实现了数据的增加、删除、修改和更新表格。
```cpp
// mytablemodel.h
#ifndef MYTABLEMODEL_H
#define MYTABLEMODEL_H
#include <QAbstractTableModel>
#include <QVector>
class MyTableModel : public QAbstractTableModel
{
public:
MyTableModel(QObject *parent = nullptr);
// 重载QAbstractTableModel的方法
int rowCount(const QModelIndex &parent = QModelIndex()) const override;
int columnCount(const QModelIndex &parent = QModelIndex()) const override;
QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole) override;
QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override;
Qt::ItemFlags flags(const QModelIndex &index) const override;
// 自定义方法
bool insertRow(int row, const QModelIndex &parent = QModelIndex());
bool removeRow(int row, const QModelIndex &parent = QModelIndex());
void setTableData(const QVector<QVector<QString>> &data);
private:
QVector<QVector<QString>> m_tableData;
};
#endif // MYTABLEMODEL_H
// mytablemodel.cpp
#include "mytablemodel.h"
MyTableModel::MyTableModel(QObject *parent)
: QAbstractTableModel(parent)
{
}
int MyTableModel::rowCount(const QModelIndex &parent) const
{
Q_UNUSED(parent)
return m_tableData.size();
}
int MyTableModel::columnCount(const QModelIndex &parent) const
{
Q_UNUSED(parent)
if (m_tableData.isEmpty())
return 0;
return m_tableData[0].size();
}
QVariant MyTableModel::data(const QModelIndex &index, int role) const
{
if (!index.isValid())
return QVariant();
if (role == Qt::DisplayRole || role == Qt::EditRole) {
int row = index.row();
int column = index.column();
return m_tableData[row][column];
}
return QVariant();
}
bool MyTableModel::setData(const QModelIndex &index, const QVariant &value, int role)
{
if (index.isValid() && role == Qt::EditRole) {
int row = index.row();
int column = index.column();
m_tableData[row][column] = value.toString();
emit dataChanged(index, index, { role });
return true;
}
return false;
}
QVariant MyTableModel::headerData(int section, Qt::Orientation orientation, int role) const
{
if (orientation == Qt::Horizontal && role == Qt::DisplayRole) {
return QString("Column %1").arg(section);
}
if (orientation == Qt::Vertical && role == Qt::DisplayRole) {
return QString("Row %1").arg(section);
}
return QVariant();
}
Qt::ItemFlags MyTableModel::flags(const QModelIndex &index) const
{
if (!index.isValid())
return Qt::NoItemFlags;
return Qt::ItemIsEditable | QAbstractTableModel::flags(index);
}
bool MyTableModel::insertRow(int row, const QModelIndex &parent)
{
beginInsertRows(parent, row, row);
QVector<QString> rowData(columnCount());
m_tableData.insert(row, rowData);
endInsertRows();
return true;
}
bool MyTableModel::removeRow(int row, const QModelIndex &parent)
{
beginRemoveRows(parent, row, row);
m_tableData.remove(row);
endRemoveRows();
return true;
}
void MyTableModel::setTableData(const QVector<QVector<QString>> &data)
{
m_tableData = data;
emit layoutChanged();
}
```
使用示例:
```cpp
// main.cpp
#include <QApplication>
#include <QTableView>
#include "mytablemodel.h"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QVector<QVector<QString>> data = {
{ "1", "Tom", "20" },
{ "2", "Jack", "25" },
{ "3", "Lucy", "18" }
};
MyTableModel model;
model.setTableData(data);
QTableView tableView;
tableView.setModel(&model);
tableView.show();
return a.exec();
}
```
以上代码实现了一个简单的表格,包括三列:编号、姓名和年龄。可以通过调用`insertRow()`、`removeRow()`和`setData()`方法来增加、删除和修改表格中的数据,表格会自动更新。