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();}