如何读取TXT文件并为每行创建独立的string类型vector？

Hey Luis, let's break this down step by step to solve your problem. First, we'll handle reading each line of your text file into its own single-element vector<string>, then we'll cover how to merge those vectors pairwise until only one remains.

Step 1: Read the File and Generate Single-Element Vectors #

In C++, you can use std::ifstream to read the file line by line, and for each line, create a new vector<string> that only contains that line. We'll store all these small vectors in a larger vector<vector<string>> to keep track of them.

Here's a complete code example:

#include <iostream>
#include <fstream>
#include <vector>
#include <string>

int main() {
    // This will hold all our single-line vectors
    std::vector<std::vector<std::string>> line_vectors;
    std::ifstream input_file("your_text_file.txt");

    // Always check if the file opened successfully
    if (!input_file.is_open()) {
        std::cerr << "Error: Could not open the file!" << std::endl;
        return 1;
    }

    std::string current_line;
    // Read each line until we reach the end of the file
    while (std::getline(input_file, current_line)) {
        // Create a new vector containing just the current line
        std::vector<std::string> single_line_vec;
        single_line_vec.push_back(current_line);
        // Add this small vector to our collection
        line_vectors.push_back(single_line_vec);
    }

    input_file.close();

    // Optional: Verify the result by printing each vector's content
    for (size_t i = 0; i < line_vectors.size(); ++i) {
        std::cout << "Vector " << i + 1 << ": " << line_vectors[i][0] << std::endl;
    }

    // Proceed to merge step here...
    return 0;
}

How this works: #

• We open the file with std::ifstream and validate the open operation to avoid errors.
• std::getline reads each line of the file into current_line (this handles lines with spaces too).
• For each line, we create a new vector<string>, add the line to it, then store that vector in line_vectors. If your file has 25 lines, line_vectors will have 25 elements, each a vector with exactly one string.

Step 2: Pairwise Merge Until One Vector Remains #

Once you have your collection of single-line vectors, you can repeatedly merge adjacent pairs until only one vector (containing all lines) is left. Here's how to implement that:

Add this code right after the file reading section (before return 0):

// Merge vectors pairwise until only one remains
while (line_vectors.size() > 1) {
    std::vector<std::vector<std::string>> merged_temp;

    // Iterate over the vectors two at a time
    for (size_t i = 0; i < line_vectors.size(); i += 2) {
        std::vector<std::string> combined;
        // Merge the current vector into combined
        combined.insert(combined.end(), line_vectors[i].begin(), line_vectors[i].end());
        
        // If there's a next vector, merge that too (handles odd counts)
        if (i + 1 < line_vectors.size()) {
            combined.insert(combined.end(), line_vectors[i+1].begin(), line_vectors[i+1].end());
        }

        merged_temp.push_back(combined);
    }

    // Replace our original collection with the merged one for the next iteration
    line_vectors = std::move(merged_temp);
}

// The final merged vector is line_vectors[0]
std::cout << "\nFinal merged vector contains " << line_vectors[0].size() << " lines." << std::endl;

How this works: #

• We use a while loop that runs as long as there's more than one vector in our collection.
• In each iteration, we create a temporary collection to hold merged vectors.
• We loop through the original vectors in steps of 2: merging vector i with i+1 (if it exists) into a new combined vector.
• After processing all pairs, we replace the original collection with the temporary merged one.
• When the loop ends, line_vectors[0] will be the single vector containing all lines from the original file.

内容的提问来源于stack exchange，提问作者Luis