C++新手求助：如何将文本文件行分配至数组索引并随机读取？

Hey there! Let's get your code working step by step. I see a few small issues in your snippet, so let's break down how to store those lines properly and pick random ones.

First, let's highlight the key fixes needed:

• You need to store lines in a container first (like an array or vector) before accessing them randomly—your current code tries to read directly to a random number, which won't work.
• getline() requires a string variable, not an integer (you tried reading into questionNumber, which is an int).
• There's a typo in your file check: you opened qArray but checked if aArray is open.

Here's a complete, working example with explanations:

#include <iostream>
#include <fstream>
#include <string>
#include <vector> // Flexible container for storing lines
#include <cstdlib> // For rand() and srand()
#include <ctime>   // For seeding the random generator

using namespace std; // Simplifies code for beginners (you can learn to avoid this later)

int main() {
    // Step 1: Create containers to hold all questions and answers
    vector<string> questions;
    vector<string> answers;
    string line;

    // Step 2: Load all lines from the questions file
    ifstream questionFile("Q_Array.txt");
    if (questionFile.is_open()) {
        while (getline(questionFile, line)) {
            questions.push_back(line); // Add each line to the questions list
        }
        questionFile.close();
    } else {
        cout << "Oops, couldn't open the questions file!" << endl;
        return 1; // Exit with error if file fails to open
    }

    // Step 3: Load all lines from the answers file
    ifstream answerFile("A_Array.txt");
    if (answerFile.is_open()) {
        while (getline(answerFile, line)) {
            answers.push_back(line); // Add each line to the answers list
        }
        answerFile.close();
    } else {
        cout << "Oops, couldn't open the answers file!" << endl;
        return 1;
    }

    // Step 4: Seed the random generator (do this ONCE at the start)
    srand(time(0));

    // Step 5: Generate a random index (0 to 99, since we have 100 lines)
    int randomIndex = rand() % 100;

    // Step 6: Show the random question and its matching answer
    cout << "Random Question: " << questions[randomIndex] << endl;
    cout << "Answer: " << answers[randomIndex] << endl;

    return 0;
}

Quick Tips for You: #

• Vectors vs Fixed Arrays: I used vector<string> because it automatically handles size (no need to pre-declare 100 elements). If you prefer a fixed array instead, replace the vectors with:

  string questions[100];
  string answers[100];
  

  Then use an index variable to assign lines in the loop:

  int i = 0;
  while (getline(questionFile, line) && i < 100) {
      questions[i] = line;
      i++;
  }
  

• File Locations: Make sure your .txt files are in the same folder as your program's executable, or use the full file path (like "C:/MyProjects/Q_Array.txt").
• Loop for Multiple Questions: If you want to keep picking random questions, wrap the random index and display code in a while(true) loop, and add a way to exit (like checking for a key press).

内容的提问来源于stack exchange，提问作者B.Crim