c++ - 从 Qt4 中的文本文件中逐字读取

Question

我想在 Qt4 中逐字读取一个文本文件(老实说，我对 Qt4 还是个新手)，我想在另一个文件中每行写入一个字。我可以在 C++ 中毫无问题地执行此操作，但是当我尝试在 Qt4 中使用 ifstream 和 ofstream 时，我遇到了错误。这是我的 Qt4 代码(在按钮的事件监听器中)

// a string that holds the text inside the File Name index
   QString str = ui->txtIndex->toPlainText();

   // Check if this is a text file
   if(str.endsWith(".txt")){
       qDebug() << "a file";

       // Create a File object that points to the file we input in the File Name
       QFile mFile("/home/mohamed/Desktop/index.dat");
       QFile readFile(str);

           // Check if there is a problem
           if(!mFile.open(QFile::WriteOnly | QFile::Append )){
               qDebug() << "Could not open the file for writing";
               return;
           }




           QTextStream in(&readFile);
           if(!readFile.open(QFile::ReadOnly | QFile::Text )){
               qDebug() << "Could not open the file for writing";
               return;
           }
           // a text stream object that will print in the the file
           QTextStream out(&mFile);

           QString mText = in.readAll();
            mText.replace("de","BURGER");
            ui->txtSearchResult->setText(mText);
           out << mText;

///home/mohamed/NetBeansProjects/indexing/fichier.txt


           mFile.flush();

            readFile.close();
           mFile.close();


   }

   else{
       qDebug() << " A FOLDER";
   }

这是我的正常 C++ 代码，运行良好!

#include <cstdlib>
#include <iostream>
#include <fstream>
#include<cstdlib>
#include <dirent.h>
using namespace std;

bool searchArray(string s, string undesired[]){
for(int i=0; i<50;i++){
    if(undesired[i] == s){
        return true;
        break;
    }
}
   return false;
 }
int main(int argc, char** argv) {
// array filled with undesired words
string undesired[50] = {"je","tu","il","nous","faut","faire","de","ce","se"};
// the directory


// the file to read from
ifstream reader("fichier");
// the file to write to
ofstream writer("index.dat", ios_base::app);
string word, message =" ";
int count = 0;


while(!reader.eof()){ // while there still is stuff to read
    reader >> word;  // read one word

    if(!searchArray(word,undesired)){ // if it's an undesired word

        writer << word <<"\t\t\t\t" <<count<<endl;// print it in the text

        cout<<"word inserted"<<endl;
     }
    count++;
      }






return 0;

Answer 1

你可以结合QString::split和 QStringList::join实现您的目标:

#include <QFile>
#include <QStringList>
#include <QCoreApplication>
#include <QTextStream>

int main()
{
    QFile ifile("in.txt");
    ifile.open(QIODevice::ReadOnly | QIODevice::Text);

    // read whole content
    QString content = ifile.readAll();
    // extract words
    QStringList list = content.split(" ");

    ifile.close();

    QFile ofile("out.txt");
    ofile.open(QIODevice::WriteOnly | QIODevice::Text);

    QTextStream out(&ofile);

    // join QStringList by "\n" to write each single word in an own line
    out << list.join("\n");

    ofile.close(); 

    return 0;
}