*屬於非類類型*的成員*的請求

Question

我正在嘗試在C ++中創建一個動態數組類，但是出現一些指針錯誤，例如。 在第23行上，我需要將pointer值（引用號）更改為this.first的值，這也是一個指針- pointer並且this.first應指向相同的值。

#include <string>
#include <iostream>
using namespace std;

class ArrayMember {
    public:
        ArrayMember* next;
        ArrayMember* prev;
        int index;
        int value;
        ArrayMember(){}
};

class Array {
    private:
        ArrayMember* first;
        ArrayMember* last;
        int length;

    public:
        int get(int index){
        ArrayMember* point;

        if(index<length/2){
            point = this.first; //error: request for member ‘first’ in ‘this’, which is of non-class type ‘Array* const’
            while(*point.index != index) { // error: request for member ‘index’ in ‘point’, which is of non-class type ‘ArrayMember*’
                point = *point.next; //error: request for member ‘next’ in ‘point’, which is of non-class type ‘ArrayMember*’
            }
            return *point.value; //error: request for member ‘value’ in ‘point’, which is of non-class type ‘ArrayMember*’
        } else if(index<length) {
            point = this.last; //error: request for member ‘last’ in ‘this’, which is of non-class type ‘Array* const’
            while(*point.index != index){ //error: request for member ‘index’ in ‘point’, which is of non-class type ‘ArrayMember*’
                point = *point.prev; //error: request for member ‘prev’ in ‘point’, which is of non-class type ‘ArrayMember*’
            }
            return *point.value; //error: request for member ‘value’ in ‘point’, which is of non-class type ‘ArrayMember*’
        }else{
            return NULL; //warning: converting to non-pointer type ‘int’ from NULL
        }
    }
    int set(int index, int value){
        //...
    }
    int indexOf(int value){
        //...
    }
    Array(){
        ArrayMember x = new ArrayMember;
        x.index = 0;
        this.first = x;
        this.last = x;
    }
};

Answer 1

變量this是一個指針 ，因此您需要使用this->first來訪問this成員。

所有指向結構的指針也是如此，您需要使用->運算符而不是. 操作員。

您當然可以使用. 運算符，並且非常接近，但是指針取消引用運算符* 優先級低於. 運算符，因此您實際上嘗試取消引用*point.next的next元素。 您需要像(*point).next這樣的括號。 但是，使用->運算符代替point->next更容易。