c++ - 使用 For 循环显示 1 个结果

Question

这是我的代码:

void IDsearch(vector<Weatherdata>temp)
{
    int userinput;
    cout << "Enter the ID of the Event and i will show you all other information: " << endl;
    cin >> userinput;
    for(unsigned int i = 0; i < temp.size();i++)
    {
        if(userinput == temp[i].eventID)
        {
            cout << "Location: " << temp[i].location << endl;
            cout << "Begin Date: " << temp[i].begindate << endl;
            cout << "Begin Time: " << temp[i].begintime << endl;
            cout << "Event Type: " << temp[i].type << endl;
            cout << "Death: " << temp[i].death << endl;
            cout << "Injury: " << temp[i].injury << endl;
            cout << "Property Damage: " << temp[i].damage << endl;
            cout << "Latitude: " << temp[i].beginlat << endl;
            cout << "Longitude: " << temp[i].beginlon << endl;
        }
    }
}

我想做的是在遍历所有值后生成它，如果 userinput 与其中任何一个都不匹配，则只打印一次“它不匹配”。我知道如果我使用 else 或 if(userinput != temp[i].eventID) 它只会多次显示“它不匹配”。我是 C++ 的新手，请帮忙。谢谢

Answer 1

您可以使用标志来记住是否找到了某些元素。

void IDsearch(const vector<Weatherdata>&temp) // use reference for better performance
{
    int userinput;
    bool found = false;
    cout << "Enter the ID of the Event and i will show you all other information: " << endl;
    cin >> userinput;
    for(unsigned int i = 0; i < temp.size();i++)
    {
        if(userinput == temp[i].eventID)
        {
            cout << "Location: " << temp[i].location << endl;
            cout << "Begin Date: " << temp[i].begindate << endl;
            cout << "Begin Time: " << temp[i].begintime << endl;
            cout << "Event Type: " << temp[i].type << endl;
            cout << "Death: " << temp[i].death << endl;
            cout << "Injury: " << temp[i].injury << endl;
            cout << "Property Damage: " << temp[i].damage << endl;
            cout << "Latitude: " << temp[i].beginlat << endl;
            cout << "Longitude: " << temp[i].beginlon << endl;
            found = true;
        }
    }
    if(!found)
    {
        cout << "it doesnt match" << endl;
    }
}