9.7 QT自我的修养

void Widget::on_pushButton_clicked()
{
    QString s1 = ui->lineEdit->text();
    QString s2 = ui->lineEdit_2->text();
    int sum = s1.toInt(0,10) + s2.toInt(0,10);
    ui->textEdit->setText(QString::number(sum , 10));
}

void Widget::on_pushButton_clicked()
{
    QString filename = QFileDialog::getOpenFileName(0,"打开");
    if (filename.isEmpty())
        return;
    FILE *fp = fopen(filename.toStdString().data(),"r");
    if (!fp)
        return;
    char buf[1024];
    QString str;
    while (!feof(fp))
    {
        fgets(buf , sizeof(buf) , fp);
        str += buf;
    }
    ui->textEdit->setText(str);
}

void Widget::on_pushButton_2_clicked()
{
    QString filename = QFileDialog::getSaveFileName(0,"保存");
    if(filename.isEmpty())
        return;
    FILE *fp = fopen(filename.toStdString().data(),"w");
    if (!fp)
        return;
    const char *str = ui->textEdit->toPlainText().toStdString().data();
    fputs(str,fp);
    fclose(fp);
}