【Qt】C++中的循环遍历

标签：c++   qt   

     本文主要讨论C++中常见的几种循环遍历操作的语法：基于迭代器、基于Qt库中的foreach关键字、基于C++11新增的for循环语句。

    QList<QString> list {"a", "b", "c", "d"};
    QList<QString>::const_iterator citer = list.cbegin();
    for (; citer != list.cend(); ++citer)
        qDebug() << (*citer);

    QList<QString> list {"a", "b", "c", "d"};
    foreach (QString s, list)
        qDebug() << s;

    QListIterator<QString> iter(list);
    while(iter.hasNext())
        qDebug() << iter.next();

#define Q_FOREACH(variable, container)                                    for (QForeachContainer<__typeof__(container)> _container_(container);     !_container_.brk && _container_.i != _container_.e;                  __extension__  ({ ++_container_.brk; ++_container_.i; }))                           for (variable = *_container_.i;; __extension__ ({--_container_.brk; break;}))                                  
    
template <typename T>
    class QForeachContainer {
    public:
        inline QForeachContainer(const T& t) : c(t), brk(0), i(c.begin()), e(c.end()) { }
        const T c;         // 将容器标识为 const 不可修改
        int brk;
        typename T::const_iterator i, e;
    };

    for (QString s : list)
        qDebug() << s;

    for (auto s : list)
        qDebug() << s;

for (auto &s : list)
    s = "x";

【Qt】C++中的循环遍历,布布扣,bubuko.com

【Qt】C++中的循环遍历

标签：c++   qt   

原文地址：http://blog.csdn.net/xiaohui_hubei/article/details/38401487