增强了C ++中的FOR循环 [英] Enhanced FOR loops in C++

问题描述

我从Java切换到C ++，我想知道C ++是否包含我在java中使用的增强型for循环，例如：

I am switching from Java to C++ and I was wondering whether C++ contains the enhanced for loops that I used in java, in example:

int[] numbers = {1,2,3,4,5,6,7,8,9,10};
for (int item : numbers) {
  System.out.println("Count is: " + item);
}

在C ++中这是否也是快捷方式？

Is this same "shortcut" possible in C++?

推荐答案

在C ++ 11中，如果你的编译器支持它，是的。它称为基于范围的。

In C++11, if your compiler supports it, yes it is. It's called range-based for.

std::vector<int> v;

// fill vector

for (const int& i : v) { std::cout << i << "\n"; }

它适用于C风格数组和任何类型的函数 begin ）和 end（）示例：

It works for C style arrays and any type that has functions begin() and end() that return iterators. Example:

class test {
    int* array;
    size_t size;
public:
    test(size_t n) : array(new int[n]), size(n)
    {
        for (int i = 0; i < n; i++) { array[i] = i; }
    }
    ~test() { delete [] array; }
    int* begin() { return array; }
    int* end() { return array + size; }
};

int main()
{
    test T(10);
    for (auto& i : T) {
        std::cout << i;   // prints 0123456789
    }
}

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