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(en.cppreference.com/w/c)上可以得到印证。 Range-Based for loop的一般形式(省略了不相关的部分)实际上等价于下面的for循环 for ( item-declaration : range-initializer ) statement item-declaration - a ...
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...
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-for)上可以得到印证。 Range-Based for loop的一般形式(省略了不相关的部分)实际上等价于下面的for循环: > `for ( item-declaration : range-initializer...
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, ...
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 ); ...
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...
The last rule (the fallback to the free-standingbegin()andend()functions) allows us to non-invasively adapt an existing container to the range-basedforloop interface. 0.2 类型推断 std::vector<int> v = {1, 2, 3, 5, 7, 11};
// although not strictly necessary for a range-based for loop // following the normal convention of returning a value from // operator++ is a good idea. return *this; } private: int _pos; const IntVector *_p_vec; }; class IntVector { public: IntVector () { } int get (int col...
2 3 4 5 6 7 8 9 10 11 12 13 14 // range-based for loop#include <iostream>#include <string>usingnamespacestd;intmain () { string str {"Hello!"};for(charc : str) { std::cout <<"["<< c <<"]"; } std::cout <<'\n'; } ...
attr(optional) for ( range_declaration : range_expression ) loop_statement 将其解释为 { auto && __range = range_expression; for (auto __begin = begin_expr, __end = end_expr; __begin != __end; ++__begin) { range_declaration = *__begin; loop_statement } } 初始化右值引用为临...