Qt5开发及实例学习之读写文本文件

新建Qt控制台应用，修改main.cpp

一、QFile读写文件

#include <QCoreApplication>
#include <QFile>
#include <QtDebug>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QFile file("C:\\Users\\Administrator\\Desktop\\read.txt");
    if(file.open(QIODevice::ReadOnly)){
        char buffer[2048];
        qint64 lineLen = file.readLine(buffer, sizeof(buffer)); //自动识别换行符
        if(lineLen != -1){  //若是读取成功，返回读取的字节数
            qDebug() << buffer;
        }
    }
    file.close();
    return a.exec();
}

二、QTextStream写文件

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

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QFile data("data.txt");
    if(data.open(QFile::WriteOnly|QFile::Truncate))  //覆盖写
    {
        QTextStream out(&data);
        out<<QObject::tr("score:")<<qSetFieldWidth(10)<<left<<90<<endl;
        //设置字段宽度为10 左对齐
    }

    return a.exec();
}

在build-qfile-Desktop_Qt_5_9_1_MinGW_32bit-Debug自动生成data.txt文件