Example Analysis of Qt text flow and data flow, buffer Operation and data Operation

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one。 Text flow and data flow

In A.Qt, file types are divided into two categories.

1. Text file-the content of the file is a readable text character

two。 Data file-the content of the file is direct binary data

QFile directly supports reading and writing of text files and data files.

B.Qt provides helper classes to simplify the reading and writing of text / data files

1. QTextStreamMouse-all written data is converted to readable text

2.QDataStreammusic-the data written is converted to binary data according to type

How to use the IO device helper class

Different Qt versions may have different data stream file formats

Version number set by void setVersion (int v) / /

Int version () const// gets the read-write version number

Code example

# include # include # include int main (int argc, char * argv []) {QCoreApplication a (argc, argv); QFile file ("C:/Users/59673/Desktop/test.hex"); if (file.open (QIODevice::WriteOnly)) {QString dt = "mylovedandanxiaohai"; double value = 3.14; file.write (dt.toStdString (). C_str ()) File.write (reinterpret_cast (& value), sizeof (value); file.close ();} if (file.open (QIODevice::ReadOnly)) {QString dt = "; double value = 0; dt = QString (file.read (19)); file.read (reinterpret_cast (& value), sizeof (value)); file.close (); qDebug () b QDebug () pi; qDebug ()