UE4 C++ 对结构体数组内元素进行排序

对结构体数组排序需要两个必要条件，一是结构体定义内重写<操作符，二是元素内必须要有可以用来排序的属性例如int、float类型的变量

案例：

.h
UENUM(BlueprintType)
enum class EOrient : uint8
{
	North,
	East,
	South,
	West,
};

USTRUCT(BlueprintType)
struct FATestActor
{
	GENERATED_USTRUCT_BODY()

public:

	UPROPERTY(EditAnyWhere, BlueprintReadWrite)
		FString str;

	UPROPERTY(EditAnyWhere, BlueprintReadWrite)
		EOrient orient;

	UPROPERTY(EditAnyWhere, BlueprintReadWrite)
		float a;

	bool operator<(const FATestActor& ATestActor) const
	{
        //>是从大到小排序，<就是从小到大
		return a > ATestActor.a;
	}
};

public:
    UFUNCTION(BlueprintCallable)
		void SortStruct(const TArray<FATestActor>& ArrayStruct);

public:
    UPROPERTY(EditAnyWhere, BlueprintReadWrite)
		TArray<FATestActor> testArrayStruct;

.cpp
void ATestActors::SortStruct(const TArray<FATestActor>& ArrayStruct)
{
    //const_cast<>()去掉const修饰符才能对数组进行更改
	const_cast<TArray<FATestActor>&>(ArrayStruct).Sort();
}