Algorithm slower after having removed C++ template/typename

Question

For learning purposes and to understand how things work, I'm trying to rewrite this without templates, in the case wstring:

#include <ctype.h>

template<typename charT>
struct my_equal 
{
    bool operator()(charT ch1, charT ch2) { return toupper(ch1) == ch2; }
};

template<typename T>
bool contains(const T& str1, const T& str2)
{
    typename T::const_iterator it = std::search(str1.begin(), str1.end(), str2.begin(), str2.end(), my_equal<typename T::value_type>());
    return (it != str1.end());    
}

I'm trying this:

struct my_equal 
{
    bool operator()(wchar_t ch1, wchar_t ch2) { return toupper(ch1) == ch2; }
};

bool contains(const wstring str1, const wstring str2)
{
    wstring::const_iterator it = std::search(str1.begin(), str1.end(), str2.begin(), str2.end(), my_equal());
    return (it != str1.end());
}

It works but it's twice or three times slower when benchmarking it. Why?

Is there something wrong in the "translation without templates"?

Also, is it possible to avoid using a struct but having the my_equal comparison directly in search(...)?

Answer 1

You omitted some ampersands. Make it,

bool contains(const wstring &str1, const wstring &str2)
{
    wstring::const_iterator it = std::search(str1.begin(), str1.end(), str2.begin(), str2.end(), my_equal());
    return (it != str1.end());
}