成员请求*in*,非类型*

Question

我正在尝试用C++创建一个动态数组类,但是我得到了一些指针错误,例如.在第23行,我需要将pointer值(引用号)更改为值this.first,也是指针 - pointer并且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

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

所有指向结构的指针都是如此,您需要使用->运算符而不是.运算符.

当然你也可以使用.运营商,和你很接近,但指针引用操作*具有较低的优先级比.运营商,所以你真正尝试取消引用next的元素*point.next.你需要像括号一样的括号(*point).next.然而,使用->操作员更容易point->next.