如何从文件中读入指定数量的字符，同时仍在遍历该文件？

要从文件中读入指定数量的字符，同时仍在遍历该文件，可以使用多种编程语言中的文件读取方法。以下是几种常见编程语言的示例代码：

Python 示例

def read_n_chars(file_path, n):
    with open(file_path, 'r') as file:
        while True:
            chunk = file.read(n)
            if not chunk:
                break
            yield chunk

# 使用示例
file_path = 'example.txt'
n = 10
for chunk in read_n_chars(file_path, n):
    print(chunk)

Java 示例

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class FileReaderExample {
    public static void main(String[] args) {
        String filePath = "example.txt";
        int n = 10;
        try (BufferedReader br = new BufferedReader(new FileReader(filePath))) {
            char[] buffer = new char[n];
            int charsRead;
            while ((charsRead = br.read(buffer, 0, n)) != -1) {
                System.out.print(new String(buffer, 0, charsRead));
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

C++ 示例

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

void read_n_chars(const std::string& file_path, int n) {
    std::ifstream file(file_path);
    if (!file.is_open()) {
        std::cerr << "Failed to open file" << std::endl;
        return;
    }

    std::string chunk;
    while (file.read(&chunk[0], n) || file.gcount()) {
        chunk.resize(file.gcount());
        std::cout << chunk;
    }
}

int main() {
    std::string file_path = "example.txt";
    int n = 10;
    read_n_chars(file_path, n);
    return 0;
}