很多语言都有Range-based for loops这个功能,现在C++终于知道把这个重要功能加进语法中了。这个功能实在不知道该怎么翻译,语文没有学到家。 基本语法 for ( range_declaration : range_expression) loop_statement 1. 比如说: 1. vector<int> vec; 2. vec.push_back( 1 ); 3. vec.push_back( 2 ); 4. ...
C++ Range-based loop: Here, we are going to learn about the range-based loop in C++, which is similar to the for-each loop.
With arrays taken care of by the first rule, the second rule makes sure that all the standard containers as well as all the user-defined ones that follow the standard sequence interface will work with range-basedforout of the box. For example, in ODB (an ORM for C++), we have the co...
When used with a (non-const) object that has copy-on-write semantics, the range-basedforloop may trigger a deep copy by (implicitly) calling the non-constbegin()member function. If that is undesirable (for instance because the loop is not actually modifying the object), it can be avoided...
直觉上c的类型应该是const char&,但是怎么推理得到c的类型呢?细究起来确实花了一番功夫。 使用auto声明的变量必须要给初始值,而这里的语法没有给初始值。Range-Based for loop应该是一种语法糖,实际上编译器应该是当成普通的for循环来处理的。 从cppreference(https://en.cppreference.com/w/cpp/language/range...
C++: Range-Based For Loops23 June 2017 by Phillip Johnston • Last updated 15 December 2021 One of the more frequently used C++ constructs I use is the range-based for loop. The range-based forloop format was introduced in C++11, so you’ll need to enable that language set (or newer...
Range-based for loop 在范围上执行for循环。 用作更易读的,相当于传统的用于循环操作范围内的值,例如容器中的所有元素。 句法 attr(optional) for ( range_declaration : range_expression ) loop_statement attr - any number of attributes range_declaration - a declaration of a named variable, ...
基于范围的for循环, Range-based for loop http://en.cppreference.com/w/cpp/language/range-for 语法: for (range_declaration:range_expression)loop_statement for (一个变量名 : 可迭代范围) { //循环语句 } 变量名的类型可以是:容器元素的类型,容器元素的引用类型,auto...
直觉上`c`的类型应该是`const char&`,但是怎么推理得到`c`的类型呢?细究起来确实花了一番功夫。 使用auto声明的变量必须要给初始值,而这里的语法没有给初始值。Range-Based for loop应该是一种语法糖,实际上编译器应该是当成普通的for循环来处理的。
namespace std; // forward-declaration to allow use in Iter class IntVector; class Iter { public: Iter (const IntVector* p_vec, int pos) : _pos( pos ) , _p_vec( p_vec ) { } // these three methods form the basis of an iterator for use with // a range-based for loop bool...