c++批量修改文件编码

你可以使用iconv库来批量修改文件编码。iconv库是一个用于字符编码转换的开源库，可以将不同编码的字符转换成目标编码。

以下是一个使用iconv库来批量修改文件编码的示例代码：

#include <iostream>
#include <fstream>
#include <iconv.h>
#include <cstring>

using namespace std;

int main(int argc, char *argv[]) {
    if (argc != 4) {
        cout << "usage: iconv-batch <from_encoding> <to_encoding> <file_list>" << endl;
        return 1;
    }

    const char* from_encoding = argv[1];
    const char* to_encoding = argv[2];
    const char* file_list = argv[3];

    ifstream list_file(file_list);
    if (!list_file.is_open()) {
        cout << "cannot open file list: " << file_list << endl;
        return 1;
    }

    char filename[256];

    while (list_file.getline(filename, 256)) {
        ifstream infile(filename);
        if (!infile.is_open()) {
            cout << "cannot open file: " << filename << endl;
            continue;
        }

        ofstream outfile((string(filename) + ".converted").c_str());
        if (!outfile.is_open()) {
            cout << "cannot open output file: " << (string(filename) + ".converted") << endl;
            continue;
        }

        // allocate iconv descriptor
        iconv_t cd = iconv_open(to_encoding, from_encoding);
        if (cd == (iconv_t)(-1)) {
            cout << "cannot create iconv descriptor" << endl;
            continue;
        }

        // convert data
        char inbuf[4096], outbuf[4096];
        size_t inbytesleft, outbytesleft;
        size_t inlen, outlen;

        while (!infile.eof()) {
            infile.read(inbuf, 4096);
            inlen = infile.gcount();
            inbytesleft = inlen;

            char* inptr = inbuf;
            char* outptr = outbuf;
            outbytesleft = 4096;

            // perform conversion
            outlen = iconv(cd, &inptr, &inbytesleft, &outptr, &outbytesleft);
            if (outlen == (size_t)(-1)) {
                cout << "iconv error: " << strerror(errno) << endl;
                break;
            }

            // write converted data to output file
            outfile.write(outbuf, 4096 - outbytesleft);
        }

        // close files
        infile.close();
        outfile.close();

        // close iconv descriptor
        iconv_close(cd);

        // remove input file
        remove(filename);

        // rename output file to input file name
        rename((string(filename) + ".converted").c_str(), filename);

        cout << "converted file: " << filename << endl;
    }

    list_file.close();

    return 0;
}

你可以编译并运行此代码，例如：

$ g++ -o iconv-batch iconv-batch.cpp -liconv
$ ./iconv-batch utf-8 gbk file_list.txt

其中，`utf-8`和`gbk`分别是源文件编码和目标文件编码，`file_list.txt`是需要批量转换编码的文件列表。程序会将文件列表中的每个文件的编码从`utf-8`转换成`gbk`，并替换原文件。如果转换过程中出现了错误，程序会输出错误信息并跳过当前文件，继续处理下一个文件。