c++ - C2061 'string' : undeclared identifier

Question

我在尝试为我的程序构建解决方案时收到“字符串”:未声明的标识符错误。我相信它与在函数声明中声明字符串类型有关。该错误首先出现在添加节点的函数签名中:

#include <iostream>
#include <string>
#include "stdafx.h"
using namespace std;

void addNode(struct Node *head, string text);

struct Node {
    string info;
    string out;
    Node* next;
};

下面是程序的其余代码:

int main()
{
    const int width = 2; // the number of cells on the X axis
    const int height = 2; // the number of cells on the Y axis
    string grid[height];

    struct Node *list = new Node;
    struct Node *listcpy;

    grid[0] = "00";
    grid[0] = "0.";

    //----------------------------------------------------------------------------------
    for (int i = 0; i < height; i++) {
        addNode(list, grid[i]);
    }

    listcpy = list; //holds pointer to beggining of list

    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width; j++)
        {
            if (list->info[j] == '0') //if current cell is a node
            {
                list->out.append(to_string(i) + " " + to_string(j) + " "); //append nodes coordinate

                if (j < width - 1) //if right cell exists
                {
                    if (list->info[j + 1] == '0') { //if there is node to the right
                        list->out.append(to_string(i) + " " + to_string(j + 1) + " ");
                    }
                    else {
                        list->out.append("-1 -1 ");
                    }

                    if (i < height - 1) //if bottom cell exists
                    {
                        if (list->next->info[j] == '0') { //if there is node at the bottom
                            list->out.append(to_string(i + 1) + " " + to_string(j) + " ");
                        }
                        else {
                            list->out.append("-1 -1 ");
                        }
                    }
                }
                list = list->next;
            }

            while (listcpy != NULL)
            {
                if (listcpy->out != "")
                {
                    cout << listcpy->out << endl;
                }
                listcpy = listcpy->next;
            }


        }
    }
}

// apending
void addNode(struct Node *head, string text)
{
    Node *newNode = new Node;
    newNode->info = text;
    newNode->next = NULL;
    newNode->out = "";

    Node *cur = head;
    while (cur) {
        if (cur->next == NULL) {
            cur->next = newNode;
            return;
        }
        cur = cur->next;
    }
}

有谁知道如何纠正这个错误？

Answer 1

很可能您启用了预编译 header 模式:

在这种情况下，#include "stdafx.h" 之前的所有内容都将被忽略。不管喜欢与否，这就是 Microsoft 实现预编译 header 功能的方式。

因此，您需要为您的项目禁用预编译 header 并删除 #include "stdafx.h"，或者您需要确保 #include "stdafx.h" 始终是每个代码文件顶部的第一行(注释除外，但无论如何它们不起任何作用)。 (这不适用于标题。)