接受用户输入，无论他们在c++中输入大写还是小写

User input accepted whether they input uppercase OR lowercase in C++

本文关键字：输入 c++ 他们 用户      更新时间：2023-10-16

这里的绝对初学者(第一篇文章)，我刚刚完成了一项任务，我必须创建一个程序，让用户创建员工工资条，然后通过姓氏，名称，员工编号等搜索显示它们。

我有一个问题，如果我为南希戴维森创建一个记录，例如，如果我搜索南希或戴维森，我可以正确地输出这个记录。如果我搜索nancy或davidson，它找不到它。

我使用一个结构体来存储每个员工的详细信息，将它们写入数据文件，然后读取该文件以显示记录。

是否有一种方法，我可以让记录仍然显示，即使我搜索NAncY?

这是我的搜索姓氏函数的代码:

    //Record search by employee SURNAME only
void searchSurname(Employee data[], int row)
{
    string surname, again;
    double wholeTot=0, wholeNet=0;
    again = "y";
    while (again=="y"||again=="Y")
    {
        row=0;
        bool found = false;
        clrscr();
        cout << "Please enter Employee SURNAME : ";
        Input(surname);
        clrscr();
        cout << "Surname Search results for " << surname << ". nnn";
        readFile (data, row);
        int stop=row;
        for ( row = 0; row < (stop) ; row++ )
            if (surname == data[row].surname)
            {
                deconvertDate(data[row].date);
                cout << "   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~" << endl 
                    << "   # Employee Number - " << RIGHT(19,2) << data[row].empnum << " #" << endl 
                    << "   # Employee Surname - " << RIGHT(18,2) << data[row].surname << " #" << endl 
                    << "   # Employee Forename - " << RIGHT(17,2) << data[row].forename << " #" << endl 
                    << "   # Department Number - " << RIGHT(17,2) << data[row].dept << " #" << endl 
                    << "   # Normal Hours Worked - " << RIGHT(15,2) << data[row].hours << " #" << endl 
                    << "   # Overtime Hours Worked - " << RIGHT(13,2) << data[row].ohours << " #" << endl 
                    << "   # Pay Rate - " << RIGHT(26,2) << data[row].rate << " #" << endl
                    << "   # Gross Pay - " << RIGHT(25,2) << data[row].grosspay << " #" << endl
                    << "   # Tax - " << RIGHT(31,2) << data[row].tax << " #" << endl
                    << "   # National Insurance - " << RIGHT(16,2) << data[row].natin << " #" << endl
                    << "   # Total Deductions - " << RIGHT(18,2) << data[row].totalDeduct << " #" << endl
                    << "   # Net Pay - " << RIGHT(27,2) << data[row].net << " #" << endl
                    << "   # Week Ending - " << RIGHT(23,2) << data[row].date << " #" << endl 
                    << "   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~" << endl << endl << endl;
                wholeTot+=data[row].grosspay;
                wholeNet+=data[row].net;
                cout << "The total recorded GROSS PAY of " << data[row].surname << " is :" << wholeTot << endl;
                cout << " and the total recorded NET PAY is :" << wholeNet << endl << endl;
                found = true;
            }
            else
                if (found = false)
                {
                    cout << "No results found for that SURNAME!" << endl;
                }

调用std::equal进行比较时，可以给出它与比较者的第四个争论。只要写一个比较器执行不区分大小写的比较:

struct CaseInsensitiveCmp
{
    bool operator()( char lhs, char rhs ) const
    {
        return ::tolower( static_cast<unsigned char>( lhs ) )
            == ::tolower( static_cast<unsigned char>( rhs ) );
    }
};

(这使用<ctype.h>中的一个参数tolower函数，这对初学者来说是最简单的解决方案。在生产中代码，当然，您将使用
中的std::ctype方面。<locale>)。

技巧通常是将存储的记录和用户输入记录转换为小写或大写。你可以使用

您需要进行不区分大小写的比较。strcasecmp可能是一个好的开始:http://linux.die.net/man/3/strcasecmp

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