QT实现计算器
void Widget::on_calBtn_clicked()
{
//得到第一个参数
float arg1 = ui->arg1LineEdit->text().toFloat();
//得到第二个参数
float arg2 = ui->arg2LineEdit->text().toFloat();
//得到运算符
QString expr = ui->comboBox->currentText();
float result;
//判断是哪个运算符并进行相应的运算
if("+" == expr)
{
result = arg1 + arg2;
}
else if("-" == expr)
{
result = arg1 - arg2;
}
else if("*" == expr)
{
result = arg1 * arg2;
}
else
{
//如果arg2为0，警告，并清空
if(0 == arg2)
{
QMessageBox::warning(this, "计算器", "除数不能为0!!!");
on_clrBtn_clicked();
return;
}
result = arg1 / arg2;
}
//将结果显示
ui->retLable->setText(QString::number(result));
}


void Widget::on_clrBtn_clicked()
{
ui->arg1LineEdit->clear();
ui->arg2LineEdit->clear();
ui->retLable->clear();
}