Sorting strings in Vector algorithm not working

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?

Please show the definition of `Item`. E.g. if `Item::type` is `const char *`, this comparison won't work. — Csq, Feb 10 '13 at 02:15
Also, to be sure to get an answer, the best is to post a minimal working example that reproduces your error. — Csq, Feb 10 '13 at 02:16

score 2 · Accepted Answer · answered Feb 10 '13 at 03:21

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);
}

score 0 · Answer 2 · edited May 23 '17 at 12:27

0

As suggested in Case insensitive string comparison C++ (2012), strcasecmp() will provide the right answer if comparing const char * strings.

If comparing C++ strings, the Boost library has is_iless(), for which the header is here, as suggested by Case insensitive string comparison in C++ (2008).

edited May 23 '17 at 12:27

Community

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answered Feb 10 '13 at 02:26

Simon

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yea it was changed from strings to char[16] and sample output is: Ingredient, weapon, armor, weapon... how could i compare the char array then to see which is supposed to be where? – AC101 Feb 10 '13 at 02:44
@AC101 What is it that's unclear to you? Use `strcasecmp()`, just like Simon said (documentation either via google or on linux via `man 3 strcasecmp`). – us2012 Feb 10 '13 at 03:22

Sorting strings in Vector algorithm not working

2 Answers2