c++ - 如何初始化 QVector> *matrix（作为班级成员）与新的？

Question

我真的尝试了一切，但找不到解决方案，我尝试先初始化外部QVector然后初始化内部，但没有成功。

Answer 1

QVector *matrix（作为类成员）带有新的？

这存在一些问题，即：

• 您不应该QVector在堆上分配 a（即作为带有 new 的指针）。

• 你应该使用QStringList更多。

我个人建议是这样的：

主文件

#include <QVector>
#include <QStringList>
#include <QDebug>

class Foo
{
    public:
        Foo() { qDebug() << matrix; }
    private:
        // Could be QStringLiteral, but you could also build it in the
        // constructor if it is dynamic
        QVector<QStringList> matrix{{"foo", "bar", "baz"}, {"hello", "world", "!"}};
};

int main()
{
    Foo foo;
    return 0;
}

主程序

TEMPLATE = app
TARGET = main
QT = core
CONFIG += c++11
SOURCES += main.cpp

构建并运行

qmake && make && ./main

输出

QVector(("foo", "bar", "baz"), ("hello", "world", "!"))

Answer 2

Probably you can't do this, because you missed one >. So try this:

#include<QDebug>
//...
private:
     QVector<QVector<QString> > *matrix = new QVector<QVector<QString> >;

And in constructor:

matrix->append(QVector<QString>() << "hello world");
qDebug() << "output: " << *matrix;

But I think that you should allocate memory in constructor. For example:

private:
     QVector<QVector<QString> > *matrix;

In constructor:

matrix = new QVector<QVector<QString> >;
matrix->append(QVector<QString>() << "hello world");
qDebug() << "output:" << *matrix;

Output in both cases:

output: QVector(QVector("hello world") )