如何解决C++中“请求访问非类类型int的成员printDetails”错误？

核心错误分析 #

报错request for member printDetails in book which is of non class type int的直接原因是：遍历书籍列表时，循环变量被错误声明为int类型（而非Book类的引用/对象），导致编译器认定book是整数，无法调用类成员函数printDetails()。

你提供的代码中展示书籍的循环写法是正确的：

for ( auto& book : bookList) {
    book.printDetails();
}

但实际运行的代码大概率误写成了：

for (int book : bookList) {
    book.printDetails();
}

这就触发了上述错误。

修正步骤 #

1. 修正循环变量类型：确保遍历vector<Book>时，循环变量是Book的引用（避免拷贝、提升效率）或对象：

   // 推荐写法：auto自动推导类型，或显式声明Book&
   for (auto& book : bookList) {
       book.printDetails();
   }
   // 显式声明写法
   for (Book& book : bookList) {
       book.printDetails();
   }
   

2. 修复输入逻辑的隐藏问题：代码中存在输入换行符残留的问题，比如输入整数后调用cin.ignore()仅跳过单个字符，可能导致后续getline读到空字符串。建议统一用cin.ignore(numeric_limits<streamsize>::max(), '\n')清除整行残留字符（需包含<limits>头文件）：

   • 修正后的插入书籍代码片段：

     case 2: {
         Book newBook;
         string title, publisherRef;
         int editions;
         double price;
         cout << "Enter title: ";
         cin.ignore(numeric_limits<streamsize>::max(), '\n'); // 清除之前输入的残留换行
         getline(cin, title);
         newBook.setTitle(title);
         cout << "Enter editions: ";
         cin >> editions;
         newBook.setEditions(editions);
         cout << "Enter publisher reference: ";
         cin.ignore(numeric_limits<streamsize>::max(), '\n'); // 清除整数输入后的换行
         getline(cin, publisherRef);
         newBook.setPublisherRef(publisherRef);
         cout << "Enter price: ";
         cin >> price;
         newBook.setPrice(price);
         bookList.push_back(newBook);
         cout << "Book added to the list.\n";
         break;
     }
     

   • 记得在文件开头添加头文件：

     #include <limits>
     

完整修正后的代码 #

#include <iostream>
#include <string>
#include <vector>
#include <limits> // 添加头文件处理输入清除

using namespace std;

class Book {
private:
    string title;
    int editions;
    string publisherRef;
    double price;
public:
    void setTitle(string t) {
        title = t;
    }
    void setEditions(int e) {
        editions = e;
    }
    void setPublisherRef(string p) {
        publisherRef = p;
    }
    void setPrice(double pr) {
        price = pr;
    }
    string getTitle() const {
        return title;
    }
    int getEditions() const {
        return editions;
    }
    string getPublisherRef() const {
        return publisherRef;
    }
    double getPrice() const {
        return price;
    }
    void printDetails()  {
        cout << "Title: " << title << endl;
        cout << "Editions: " << editions << endl;
        cout << "Publisher reference: " << publisherRef << endl;
        cout << "Price: " << price << endl;
    }
};

int main() {
    vector<Book> bookList;
    int choice;
    do {
        cout << "Main menu\n";
        cout << "1. Book\n";
        cout << "0. Exit\n";
        cout << "Enter your choice: ";
        cin >> choice;
        switch (choice) {
            case 1: {
                int bookChoice;
                do {
                    cout << "Book submenu\n";
                    cout << "1. Display\n";
                    cout << "2. Insert\n";
                    cout << "0. Back\n";
                    cout << "Enter your choice: ";
                    cin >> bookChoice;
                    switch (bookChoice) {
                        case 1: {
                            if (bookList.empty()) {
                                cout << "There are no books in the list.\n";
                            } else {
                                cout << "Book list:\n";
                                for (auto& book : bookList) {
                                    book.printDetails();
                                }
                            }
                            break;
                        }
                        case 2: {
                            Book newBook;
                            string title, publisherRef;
                            int editions;
                            double price;
                            cout << "Enter title: ";
                            cin.ignore(numeric_limits<streamsize>::max(), '\n');
                            getline(cin, title);
                            newBook.setTitle(title);
                            cout << "Enter editions: ";
                            cin >> editions;
                            newBook.setEditions(editions);
                            cout << "Enter publisher reference: ";
                            cin.ignore(numeric_limits<streamsize>::max(), '\n');
                            getline(cin, publisherRef);
                            newBook.setPublisherRef(publisherRef);
                            cout << "Enter price: ";
                            cin >> price;
                            newBook.setPrice(price);
                            bookList.push_back(newBook);
                            cout << "Book added to the list.\n";
                            break;
                        }
                        case 0: {
                            break;
                        }
                        default: {
                            cout << "Invalid choice. Please try again.\n";
                            break;
                        }
                    }
                } while (bookChoice != 0);
                break;
            }
            case 0: {
                break;
            }
            default: {
                cout << "Invalid choice. Please try again.\n";
                break;
            }
        }
    } while (choice != 0);

    return 0;
}

内容的提问来源于stack exchange，提问作者asdo