QT常用转换

**Qt 常用转换**

Qt 是一个跨平台的应用程序开发框架，提供了大量的功能和工具。其中，转换是 Qt 中非常重要的一部分，它们使得我们能够轻松地在不同类型之间进行数据的转移。在本文中，我们将介绍一些常用的 Qt 转换。

###1. `qint8`、`quint8` 和 `qint16` 的转换这些类型是 Qt 中用于表示整数值的类型，它们分别对应于 C++ 中的 `char`、`unsigned char` 和 `short int` 类型。我们可以使用以下函数来进行转换：

* `qint8`: `Q_INT8_C(int)` 或 `static_cast(int)`
* `quint8`: `Q_UINT8_C(unsigned int)` 或 `static_cast(unsigned int)`
* `qint16`: `Q_INT16_C(int)` 或 `static_cast(int)`

示例代码：

cpp#include <qglobal.h>
#include <iostream>

int main() {
 qint8 a = Q_INT8_C(10);
 quint8 b = Q_UINT8_C(20);
 qint16 c = Q_INT16_C(30);

 std::cout << "a: " << static_cast<int>(a) << std::endl;
 std::cout << "b: " << static_cast<unsigned int>(b) << std::endl;
 std::cout << "c: " << static_cast<int>(c) << std::endl;

 return0;
}

cpp#include <qglobal.h>
#include <iostream>

int main() {
 qint32 a = Q_INT32_C(10);
 quint32 b = Q_UINT32_C(20);

 std::cout << "a: " << static_cast<int>(a) << std::endl;
 std::cout << "b: " << static_cast<unsigned int>(b) << std::endl;

 return0;
}

cpp#include <qglobal.h>
#include <iostream>

int main() {
 qint64 a = Q_INT64_C(10);
 quint64 b = Q_UINT64_C(20);

 std::cout << "a: " << static_cast<int>(a) << std::endl;
 std::cout << "b: " << static_cast<unsigned int>(b) << std::endl;

 return0;
}

cpp#include <qglobal.h>
#include <iostream>

int main() {
 qreal a = QREAL_C(10.5f);
 std::cout << "a: " << static_cast<float>(a) << std::endl;

 return0;
}

cpp#include <qglobal.h>
#include <iostream>

int main() {
 bool a = Q_BOOL_C(true);
 std::cout << "a: " << static_cast<bool>(a) << std::endl;

 return0;
}

cpp#include <qglobal.h>
#include <iostream>

int main() {
 char a = Q_CHAR_C('a');
 std::cout << "a: " << static_cast<char>(a) << std::endl;

 return0;
}

cpp#include <qglobal.h>
#include <iostream>

int main() {
 wchar_t a = Q_WCHAR_C(L'a');
 std::cout << "a: " << static_cast<wchar_t>(a) << std::endl;

 return0;
}

cpp#include <qglobal.h>
#include <iostream>

int main() {
 QString a = QSTRING_C("Hello, World!");
 std::cout << "a: " << static_cast<const char*>(a.toLocal8Bit().constData()) << std::endl;

 return0;
}

cpp#include <qglobal.h>
#include <iostream>

int main() {
 QByteArray a = QBYTEARRAY_C("Hello, World!");
 std::cout << "a: " << static_cast<const char*>(a.constData()) << std::endl;

 return0;
}

cpp#include <qglobal.h>
#include <iostream>

int main() {
 QVariant a = QVARIANT_C("Hello, World!");
 std::cout << "a: " << static_cast<const char*>(a.toString().toLocal8Bit().constData()) << std::endl;

 return0;
}