Question

我如何分离以下语句，以便我可以显示"123"搜索的信息而不显示"topic not supported"，因为它不是第一次搜索的"decimals"？

string sentence;
string search;
string sentence2;
string search2;
size_t position2;

cin >> choosetopic;

switch (choosetopic) 
{
    case 1:
        cout << "Please enter the name of the topic you need help with.";

        cin >> sentence;
        system("cls");

        cout << "Topic: " << sentence << endl;
        cout << "\n";

        size_t pos;
        search = "Decimals";
        search = "decimals";
        search = "decimal";
        search = "Decimal";
        pos = sentence.find(search);
        if (pos != std::string::npos)
            cout << "blah blah" << std::endl;
        else
            cout << "Topic not yet supported, please try another. View 'Help' on the main menu to see supported topics. " << endl;

        cin >> sentence;
        cout << "Topic: " << sentence << endl;
        cout << "\n";
        search = "123";
        pos = sentence.find(search);
        if (pos != std::string::npos)
            cout << "12313" << std::endl;
        else
            cout << "Topic not yet supported, please try another. View 'Help' on the main menu to see supported topics. " << endl;

Answer 1

尝试更像这样的东西：

int containsTopic(const std::string &s, const char **topics, int numTopics)
{
    for(int i = 0; i < numTopics; ++i)
    {
        if (s.find(topics[i]) != std::string::npos)
            return i;
    }
    return -1;
}

std::string sentence;
int choosetopic;

std::cin >> choosetopic;
std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');

switch (choosetopic) 
{
    case 1:
    {
        std::cout << "Please enter the name of the topic you need help with.";

        std::cin >> sentence;
        std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
        // better: std::getline(std::cin, sentence);

        system("cls");

        std::cout << "Topic: " << sentence << std::endl;
        std::cout << "\n";

        char* search[] = {"Decimal", "decimal", "123"};

        int idx = containsTopic(sentence, search, 3);
        switch (idx)
        {
            case 0:
            case 1:
                std::cout << "blah blah" << std::endl;
                break;

            case 2:
                std::cout << "12313" << std::endl;
                break;

            default:
                std::cout << "Topic not yet supported, please try another. View 'Help' on the main menu to see supported topics. " << std::endl;
                break;
        }

        //...

        break;
    }

    //...
}

我如何分离这些陈述？

1 个答案: