number()可以转换int to QString
void Widget::calc()
{
int first = ui->firstLineEdit->text().toInt();
int second = ui->secondLineEdit->text().toInt();
int result = first + second;
ui->resultLineEdit->setText(QString::number(result));
}
void Widget::calc()
{
int first = ui->firstLineEdit->text().toInt();
int second = ui->secondLineEdit->text().toInt();
int result = first + second;
ui->resultLineEdit->setText(QString::number(result));
}