QMessageBox::warning(NULL, "warning对话框", "你现在已完成修改，是否保存，是否结束程序", QMessageBox::Save | QMessageBox::Cancel, QMessageBox::Discard, QMessageBox::Save);修改一下

QMessageBox::StandardButton reply = QMessageBox::warning(nullptr, "Warning", "You have made changes. Do you want to save them?", QMessageBox::Save | QMessageBox::Cancel | QMessageBox::Discard, QMessageBox::Save); if (reply == QMessageBox::Save) { // Save changes } else if (reply == QMessageBox::Cancel) { // Cancel changes } else { // Discard changes }