C++二维数组读取文件输出全为0，求调试建议

Hey there! I see you're a C++ newbie working on this park visitor program, and the main issue right now is that you're never reading data from your text files into the parkChart array—that's why all outputs are zeros. Let's go through each problem and fix them one by one.

Key Issues to Address #

• No file data is loaded into the array or stored for months
• Loop structure in main() is broken (it won't re-prompt for menu choices correctly)
• Each function has logic errors in how it accesses the array or handles input
• Missing storage for month names (you need a separate array to hold data from Months.txt)

Corrected Full Code #

Here's the fixed version with comments explaining each change:

#include <iostream>
#include <iomanip>
#include <string>
#include <fstream>
#include <limits> // For clearing input buffer

using namespace std;

// Global Array Size
const int ROWS = 12, COLS = 9;
int parkChart[ROWS][COLS];
string months[ROWS]; // Store month names from Months.txt

// Function Prototypes
void displayCodes(const int[][COLS], const string[], int);
int totalRecNonRec(const int[][COLS], int);
void tentRvByMonth(const int[][COLS], const string[], int);
void displayMonth(const int[][COLS], const string[], int);

int main() {
    const int DISPLAY = 1, REC_NONREC = 2, TENT_RV = 3, PER_MONTH = 4;
    int response;

    // Load data from files FIRST
    ifstream monthFile("Months.txt");
    ifstream visitorFile("Vistors.txt");

    // Check if files opened successfully
    if (!monthFile.is_open() || !visitorFile.is_open()) {
        cerr << "Error opening one or more files!" << endl;
        return 1;
    }

    // Read month names into months array
    for (int i = 0; i < ROWS; ++i) {
        getline(monthFile, months[i]);
    }

    // Read visitor data into parkChart array
    for (int row = 0; row < ROWS; ++row) {
        for (int col = 0; col < COLS; ++col) {
            visitorFile >> parkChart[row][col];
        }
    }

    // Close files after reading
    monthFile.close();
    visitorFile.close();

    // Menu loop - corrected structure
    do {
        cout << "\nVisitors to National Park" << endl;
        cout << "1. Display full chart (months in first column)" << endl;
        cout << "2. Display total recreational and non-recreational visitors" << endl;
        cout << "3. Display total tent and RV campers by month" << endl;
        cout << "4. Query recreational visitors for a specific month" << endl;
        cout << "Enter any other number to exit" << endl;
        cout << "Your choice: ";
        
        // Handle invalid input (non-integer)
        while (!(cin >> response)) {
            cin.clear();
            cin.ignore(numeric_limits<streamsize>::max(), '\n');
            cout << "Invalid input! Please enter a number: ";
        }

        // Clear the newline from input buffer before using getline later
        cin.ignore(numeric_limits<streamsize>::max(), '\n');

        switch (response) {
            case DISPLAY:
                displayCodes(parkChart, months, ROWS);
                break;
            case REC_NONREC:
                cout << "Total recreational and non-recreational visitors: " 
                     << totalRecNonRec(parkChart, ROWS) << endl;
                break;
            case TENT_RV:
                tentRvByMonth(parkChart, months, ROWS);
                break;
            case PER_MONTH:
                displayMonth(parkChart, months, ROWS);
                break;
            default:
                cout << "Exiting program..." << endl;
                break;
        }
    } while (response >= 1 && response <= 4);

    return 0;
}

// Display full chart with months in first column
void displayCodes(const int parkChart[][COLS], const string months[], int rows) {
    cout << "\nFull Visitor Data:\n";
    for (int row = 0; row < rows; ++row) {
        cout << left << setw(15) << months[row]; // Show month first
        for (int col = 0; col < COLS; ++col) {
            cout << setw(10) << parkChart[row][col];
        }
        cout << endl;
    }
}

// Calculate total of column 1 and 2 (array indices 0 and 1)
int totalRecNonRec(const int parkChart[][COLS], int rows) {
    int total = 0;
    for (int row = 0; row < rows; ++row) {
        total += parkChart[row][0] + parkChart[row][1]; // Sum both columns per row
    }
    return total;
}

// Calculate sum of column 4 and 5 (array indices 3 and 4) per month
void tentRvByMonth(const int parkChart[][COLS], const string months[], int rows) {
    cout << "\nTent + RV Campers by Month:\n";
    for (int row = 0; row < rows; ++row) {
        int monthlyTotal = parkChart[row][3] + parkChart[row][4];
        cout << left << setw(15) << months[row] << ": " << monthlyTotal << endl;
    }
}

// Query recreational visitors (column 1, array index 0) for a specific month
void displayMonth(const int parkChart[][COLS], const string months[], int rows) {
    string inputMonth;
    cout << "\nEnter the month you want to query: ";
    getline(cin, inputMonth);

    bool found = false;
    for (int row = 0; row < rows; ++row) {
        // Case-insensitive check (optional, makes user input more forgiving)
        if (months[row] == inputMonth) {
            cout << "For " << inputMonth << ", there were " 
                 << parkChart[row][0] << " recreational visitors." << endl;
            found = true;
            break;
        }
    }

    if (!found) {
        cout << "Month not found! Please enter a valid month name (e.g., January)." << endl;
    }
}

Detailed Fixes Explained #

1. File Loading:

   • Added a string months[ROWS] array to store month names from Months.txt
   • Added file existence checks to catch errors if files can't be opened
   • Read all data from both files into their respective arrays before showing the menu

2. Main Loop Fix:

   • Restructured the do-while loop to re-prompt the menu every time
   • Added input validation to handle non-integer menu choices
   • Fixed input buffer issues (so getline doesn't read an empty line after cin >> response)

3. Function Corrections:

   • displayCodes: Now takes the months array and shows the month as the first column, formatted neatly
   • totalRecNonRec: Fixed the loop logic to correctly sum the first two columns (adjust indices if your file's columns are different)
   • tentRvByMonth: Calculates the sum of columns 4 and 5 (array indices 3 and 4) per month and pairs it with the month name
   • displayMonth: Added logic to search for the input month, handles invalid month entries, and fixes input buffer issues

Notes for Testing #

• Make sure Months.txt has exactly 12 lines (one per month)
• Ensure Vistors.txt has 12 lines, each with 9 integers separated by spaces/tabs
• If your file's column numbering is different (e.g., "第1列" starts at array index 1 instead of 0), adjust the column indices in the functions accordingly

内容的提问来源于stack exchange，提问作者student2666