1、代码:

void MainWindow::on_pushButton_clicked()
{
QString str = "";
QString str01 = str.leftJustified(, '');
qDebug() << str01;
str01 = str.rightJustified(, '');
qDebug() << str01;
str01 = str.rightJustified(, '');
qDebug() << str01;
}

2、控制台输出:

"500"
"00005"
"05"

3、

4、

5、

05-11 15:07