Replacing a text in file in C++ using Qt -

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i using qt library , trying change contents of file. want replace text stored in tok2 fname. updated code:

qfile file(destpath); if (file.open(qiodevice::readwrite | qiodevice::text)) {   qtextstream stream(&file);   while (!stream.atend())   {     qstring line = stream.readline();     qstringlist tokenlist = line.split("\t");             if ( tokenlist.count() == 2 && (tokenlist.at(0).endswith("file",qt::caseinsensitive)))     {          qstring tok1 = tokenlist.at(0).trimmed();           qstring tok2 = tokenlist.at(1).trimmed();       qfileinfo relpath(tok2);       qstring fname = relpath.filename();          qstring newline = tok1.append(" ").append(fname);         qstring oldline = tok1.append(" ").append(tok2);         qdebug() << "original line: " << oldline << "new line" << newline;         qtextstream in(&file);          while (!in.atend())         {           qstring line = in.readline();           qstring outline = line.replace(qstring(oldline), qstring(newline));           in << outline;         }       }     }                          } }

original contents of tok2 in format ../something/filename.ext , have replace filename.ext above code not replacing contents of tok2 fname, in short unable write in file.

you making things complicated.

const qstring dostuff(const qstring &str) {     // change string want }  int main(int argc, char *argv[]) {     qcoreapplication app(argc, argv);      const qstring filepath = "/home/user/test.txt";     qtextcodec *codec = qtextcodec::codecforlocale();      // read file     qfile file(filepath);     if (!file.open(qfile::readonly)) {         qdebug() << "error opening read: " << file.errorstring();         return -1;     }     qstring text = codec->tounicode(file.readall());     file.close();      text = dostuff(text);      // write file     if (!file.open(qfile::writeonly)) {         qdebug() << "error opening write: " << file.errorstring();         return -2;     }     file.write(codec->fromunicode(text));     file.close();      return 0; }

works fast enough, if file size less amount of ram.


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