Question

I have a vector of struct items that has a string inside. I am trying to sort the vector of items by having the string inside the items in alphabetical order… so far I have:

vector<Item> sorter;

std::sort(sorter.begin(), sorter.end(), SortHelp);

//predcate function
bool SortHelp(Item const& one, Item const& two) 
{
    return one.type < two.type;
}

*type is the string that I am using to sort

How could I change the predicate function to sort the strings alphabetically?

Answer 1

The following function will do a case-insensitive compare on two std::strings without external libraries (it is C++11 though).

bool caseinsensitivecompare(string s1, string s2) {
    locale loc;
    std::transform(s1.begin(),s1.end(),s1.begin(), 
                   [loc](char c){return std::toupper<char>(c,loc);});
    std::transform(s2.begin(),s2.end(),s2.begin(), 
                   [loc](char c){return std::toupper<char>(c,loc);});
    return (s1 < s2);
}