c++ - 请求*中的成员*，属于非类类型*

Question

我试图在 C++ 中创建一个动态数组类，但我遇到了一些指针错误，例如。在第 23 行，我需要将 pointer 值(引用编号)更改为 this.first 的值，这也是一个指针 - pointer 和this.first 应该指向相同的值。

#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

this 变量是一个指针，因此您需要使用this->first 来访问this< 的成员.

同样适用于所有指向结构的指针，您需要使用-> 运算符而不是. 运算符。

您当然可以使用 . 运算符，并且您非常接近，但是指针解引用运算符 * 具有较低的 precedence而不是 . 运算符，因此您实际上尝试取消引用 *point.next 中的 next 元素。您需要像 (*point).next 这样的括号。但是，使用 -> 运算符比 point->next 更容易。