错误：“无效的比较器”使用自定义比较功能排序时 [英] Error:"invalid comparator" when sorting using custom comparison function

问题描述

我正在尝试对一些整数进行排序，使奇数后跟偶数。我正在使用Visual Studio 2015。

I am trying to sort some integers and make odd integers followed by even ones. I am using Visual Studio 2015.

这是我的代码：

int w[]={1,2,3,4,5,6};
sort(w,w+6,[](const int&i,const int&j)->bool {
return (i&1)==(j&1)//When both are odd or even, the order is OK
||i&1;//if one is odd and one is even,check if the first one is odd
});

在执行时，遇到一个错误，提示表达式：无效的比较器。我不知道为什么会导致此错误。如何修改它？

When executed, it encounters an error says "Expression: invalid comparator". I don't know why it would cause this error. How to modify it?

推荐答案

sort 需要严格弱排序。您的比较器不是一个。除其他外，对于严格的弱排序， comp（x，x）必须为 false 。

sort requires a strict weak ordering. Your comparator isn't one. Among many other things, for a strict weak ordering, comp(x, x) must be false.

sort 仍然是错误的算法（是的，您可以将其扭曲以执行所需的操作；不，您不应不这样做）。您想要做的是一个分区。为此，我们有 std :: partition ：

sort is the wrong algorithm for this anyway (yes, you can contort it to do what you want; no, you shouldn't do it). What you want to do is a partition. For that, we have std::partition:

std::partition(std::begin(w), std::end(w), [](int x) { return x % 2 != 0; });

或 std :: stable_partition ，如果您希望分区稳定（保留元素的相对顺序）。

Or std::stable_partition, if you want the partition to be stable (preserve the relative order of elements).

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