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 { auto && __range =range_expression; for (auto __begin =begin_expr,...
所有的STL标准容器都适用于该“范围”,例如vector、string等等。数组也同样可以,只要定义了begin()和end()方法的任何“范围”都可以使用for来循环迭代容器里面的元素,如istream。 语法: for(range_declaration:range_expression)loop_statement 上述代码的效果类似于: (__range,__beginand__endare for exposition onl...
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}; const std::vector<int> cv = {1, 2, 3, 5, 7, 11...
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...
for(inti:{1,2,3})inti=1;// error: redeclaration Temporary range initializer Ifrange-initializerreturns a temporary, its lifetime is extended until the end of the loop, as indicated by binding to the forwarding reference/* range */.
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-for)上可以得到印证。 Range-Basedfor loop的一般形式(省略了不相关的部分)实际上等价于下...
The loop iterates in a forward direction. If you want to iterate backward, you would need to use the standard for loop format with rbegin() and rend() iterators.Example LoopsI think the cppreference example is very clear and demonstrates the various types of accesses you can use:#...
在C++98标准中,基于范围的for循环(range-based for loop)是不被支持的。这种循环结构是C++11及以后版本中引入的,用于简化对容器(如std::vector、std::list等)或数组的遍历。基于范围的for循环自动处理容器的开始和结束迭代器,使得代码更加简洁易读。 替代方案以在C++98中实现类似功能 在C++98中,你可以使用传统的...
In lesson 16.6 -- Arrays and loops, we showed examples where we used a for-loop to iterate through each element of an array using a loop variable as an index. Here’s another example of such: #include <iostream> #include <vector> int main() { std::vector fibonacci { 0, 1, 1, ...
Edit & run on cpp.sh Last edited onMay 21, 2020 at 4:11am May 21, 2020 at 4:45am QueenJJ(15) This is what I have so far, not sure if it is correct 1 2 3 4 5 6 7 8 9 10 for(constauto& inner_vec : magic_square) {intsum(0);for(intelement : inner_vec) { sum +...