Sind Gleitkommazahlen sortierbar? Wegen NaN gibt es keine Ordnung und das Sortieren mit NaN im Datensatz schl\u00e4gt fehlt.
\nAber man kann sich schnell selbst eine Ordnung bauen:<\/p>\n
\r\n#include <vector>\r\n#include <algorithm>\r\n#include <iostream>\r\n#include <limits>\r\n#include <cmath>\r\n\r\nusing namespace std;\r\nusing nl = numeric_limits<double>;\r\n\r\nint main() {\r\n cout << boolalpha;\r\n\r\n vector<double> v { 1.0, 2.0, 0.0, 1.0\/3.0, -0.0,\r\n nl::quiet_NaN(), nl::infinity(), nl::epsilon(), nl::denorm_min(),\r\n nl::max(), nl::min(), nl::lowest()\r\n };\r\n\r\n sort(v.begin(), v.end());\r\n\r\n for(const auto x : v) {\r\n cout << x << " ";\r\n }\r\n cout << "\\nis sorted " << is_sorted(v.begin(), v.end()) << " << offensichtlich falsch\\n";\r\n\r\n auto comp = [](const auto lhs, const auto rhs) {\r\n if(isnan(lhs)) return false;\r\n if(isnan(rhs)) return true;\r\n return lhs<rhs;\r\n };\r\n\r\n sort(v.begin(), v.end(), comp);\r\n\r\n for(const auto x : v) {\r\n cout << x << " ";\r\n }\r\n cout << "\\nis sorted " << is_sorted(v.begin(), v.end()) << "\\n";\r\n}\r\n<\/pre>\n\n-1.79769e+308 0 -0 0.333333 1 2 nan<\/strong> 4.94066e-324 2.22507e-308 2.22045e-16 1.79769e+308 inf \r\nis sorted true << offensichtlich falsch\r\n-1.79769e+308 0 -0 4.94066e-324 2.22507e-308 2.22045e-16 0.333333 1 2 1.79769e+308 inf nan<\/strong> \r\nis sorted true << richtig<\/pre>\n<\/blockquote>\n","protected":false},"excerpt":{"rendered":"Sind Gleitkommazahlen sortierbar? Wegen NaN gibt es keine Ordnung und das Sortieren mit NaN im Datensatz schl\u00e4gt fehlt. Aber man kann sich schnell selbst eine Ordnung bauen: #include <vector> #include <algorithm> #include <iostream> #include <limits> #include <cmath> using namespace std; using nl = numeric_limits<double>; int main() { cout << boolalpha; vector<double> v { 1.0, 2.0, […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[17],"class_list":["post-3711","post","type-post","status-publish","format-standard","hentry","category-allgemein","tag-cpp"],"_links":{"self":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/3711","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3711"}],"version-history":[{"count":7,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/3711\/revisions"}],"predecessor-version":[{"id":3718,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/3711\/revisions\/3718"}],"wp:attachment":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3711"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3711"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3711"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}