c++ - Qt光标问题？

Question

    QTextCursor prev_Curosr=ui->Input->textCursor();
    qDebug()<<prev_Curosr.position();
    QTextCursor currentCurosr=prev_Curosr;
    
    int num1=string_to_int(expr1);
    int num2=string_to_int(expr2);  /*计算结果*/

    /*  Display the result   */
    ui->Input->appendPlainText(QString::number(num1+num2));
    qDebug()<<"Hello"<<currentCurosr.position()<<endl;
    qDebug()<<prev_Curosr.position();

    if(prev_Curosr.position()==prev_Curosr.position())
       ui->Input->insertPlainText(QString("Hello world"));
    return 0;
}

3
Hello 5

5

求问：为什么prev_Cursor currentCursor会在appendPlainText执行之后变成5，没道理呀

Answer 1

The problem is solved, ask and answer your own questions.
TextCursor returns an absolute cursor, use

TextCursor.deleteChar()
setPos
position()

Function can solve it