void searchlearningcontent(string keyword) { for (const auto& content : learningcontents) { if (content.title.find(keyword) != string::npos || content.description.find(keyword) != string::npos) { cout << "title: " << content.title << endl; cout << "description: " << content.description << endl; cout << "priority: " << content.priority << endl; cout << "---------------------------" << endl; }是什么意思