在链接列表.cpp中使用的错误C4703可能未初始化的本地指针变量'x'

Question

我在代码中收到一条错误消息，内容为

Error   C4703   potentially uninitialized local pointer variable 'x' used   Project1    
Error   C4703   potentially uninitialized local pointer variable 'y' used   Project1    

，我不确定为什么。我一直在研究，并且可以找到解决此问题的正确方法。这是我的Linklist.cpp文件

如果您还想要链表文件的其余部分，那么这里是一个链接，我将其粘贴到其中 https://repl.it/repls/MushyMonthlySpyware

LinkedList::ErrorCode LinkedList::getListElement(int posStart, int posEnd, ListElement rv[]) const {

    int size = getListSize();
    if (posStart < 0 || posStart >= size) {
        return ILLEGAL_LIST_POSITION;
    }
    if (posEnd < 0 || posEnd >= size) {
        return ILLEGAL_LIST_POSITION;
    }
    if (posEnd < posStart) {
        return ILLEGAL_LIST_POSITION;
    }

    int index = 0;

    Node *x, *y;
    Node *a = first;
    int count = 0;
    while (a != NULL) {
        if (posStart == count) {
            x = a;
        }
        if (posEnd == count) {
            y = a;
        }
        a = a->next;
        count++;
    }

    a = x;
    while (a != y->next) {
        rv[index++] = a->data;
        a = a->next;
    }

    return NO_ERROR;

}