Hi, Meryl Silverburgh wrote:
Hi,
I need to compare 2 strings in this format (a integer separator by '/': /1/1 /1/1/2 /1/1/3
so "/1/1" is less than "/1/1/2" and "/1/1/2" is less than " "/1/1/3".
Is there anything in Boost string library to help me to write such a comparison? Is there a string iterator which literates base on the separator '/'? My idea is to find an iterator to loop thru the string based on separator '/'.
There is a split_iterator which you can use. And there is a generic lexicographical_compare function. I've got an idea that might work. But it is a little elaborate. First, tokenize your string using split, but store the result to vector<iterator_range>. Then define a comparison function, that will take the two iterator_ranges and compare them. Note, that in this case, tha range should hold an integer string. Then simply use lexicographical_compare for the comparison. vector<iterator_range> vec1; split(vec, s1); vector<iterator_range> vec2; split(vec, s2); if(lexicographical_compare(vec1, vec2, integer_compare)) { // s1 is less } You can even throw away the vector, and directly create an iterator_range from the split_iterator. This way you may spare some unnecessary tokenization. typedef split_iterator<string::const_iterator> string_split; iterator_range<string_split> r1( make_split_iterator(s1, is_any_of("/")), string_split()) iterator_range<string_split> r2( make_split_iterator(s2, is_any_of("/")), string_split()) if(lexicographical_compare(vec1, vec2, integer_compare)) { // s1 is less } Best Regards, Pavol.