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**编辑：**代码使用SO回复的提示更新。编译时没有错误，列表打印为空。数量没有更新。
**原帖子：**这是为学校准备的，我似乎无法让它增加项目。它成功地打开了文件，但随后打印的事件为0，即使我在菜单中输入的每个项目至少有1。这不是我的全部代码，但它是我的类的代码，因为我认为这可能是我出错的地方。此外，我的菜单不会识别无效输入，即使if/else的else部分在那里捕获它。它只是进入了一个打印菜单的无限循环。我对所有的反馈和/或链接的资源比Zybooks更好地教我什么，我在这里错过了。

class ItemCounter {
private:
    map <string, int> itemFrequency;
    string inputFile = "CS210_Project_Three_Input_File.txt";
    string outputFile = "itemTracker.dat";
public:
    void loadInputFile() {
        ifstream file(inputFile);
        // OPEN conditions
        if (file.is_open()) {
            string itemName;
            while (getline(file, itemName)) {
                int itemQuantity = 0;
                // Update item count
                itemFrequency[itemName] += itemQuantity;
                // Exception check for string conversion
                try {
                    itemQuantity = stoi(itemName);
                }
                catch (const invalid_argument& e) {
                    cout << "Error: Invalid Entry Found in Input File." << endl;
                    continue;
                }
            }
            // Close open file
            file.close();
        }
        // Else statement if file won't open
        else {
            cout << "Error: Could Not Open Input File" << endl;
            cout << endl;
        }
    }
    // Function to save new data to external file
    void saveOutputFile() {
        ofstream file(outputFile);
        if (file.is_open()) {
            for (auto& item : itemFrequency) {
                file << item.first << " " << item.second << endl;
            }
            file.close();
        }
        else {
            cout << "Error: Could Not Open Output File - Data Not Saved" << endl;
            cout << endl;
        }
    }
    // Function to display item occurrences
    void displayItemCount(string itemName) {
        int count = itemFrequency[itemName];
        cout << "Total Item Occurances for " << itemName << ": " << count << endl;
    }
    //Function to count and display total item counts of whole list
    void displayTotals () {
        for (auto& item : itemFrequency) {
            cout << item.first << " " << item.second << endl;
        }
    }
    // Function to count items in the list and print as histogram
    void displayItemsHistogram() {
        for (auto& item : itemFrequency) {
            cout << item.first << " ";
            for (int i = 0; i < item.second; i++) {
                cout << "*";
            }
            cout << endl;
        }
    }
};
    // Function to save new data to external file
    void saveOutputFile() {
        ofstream file(outputFile);
        if (file.is_open()) {
            for (auto& item : itemFrequency) {
                file << item.first << " " << item.second << endl;
            }
            file.close();
        }
        else {
            cout << "Error: Could Not Open Output File - Data Not Saved" << endl;
            cout << endl;
        }
    }
};
int main() { 
    ItemCounter itemCounter;
    itemCounter.loadInputFile();
    itemCounter.saveOutputFile();
    int menuChoice = 0;
    while (menuChoice != 4) {
        cout << "Main Menu" << endl;
        cout << endl;
        cout << "1. Stuff" << endl;
        cout << "2. Stuff" << endl;
        cout << "3. Stuff" << endl;
        cout << "4. Exit" << endl;
        cout << "Please make a selection: ";
        cin >> menuChoice;
        cout << endl;
        if (menuChoice == 1) {
            string itemName;
            cout << "Enter search term: ";
            cin >> itemName;
            cout << "FIX ME:" << endl;
        }
        else if (menuChoice == 2) {
            cout << "FIX ME" << endl;
        }
        else if (menuChoice == 3) {
            cout << "FIX ME" << endl;
        }
            
        else if (menuChoice == 4) {
            cout << "Program Terminated" << endl;
        }
        else {
            cout << "Invalid Selection, try again." << endl;
        }
    }
    return 0;
}