Man hat ein Array von Objekten einer abgeleiteten Klasse.
\nDa new[] nur den Default Konstruktor aufruft, kann man keine schon existierende Instanz der Basisklasse mitgeben.
\nFolgender Code zeigt, wie man die Basisinstnaz nachtr\u00e4glich \u00e4ndern kann.<\/p>\n
class rawData class extendedData : public rawData int main () extendedData *knotenext = new extendedData[2]; cout << knotenext[0].x << endl;\n cout << knotenext[0].a << endl;\n\n \/\/ do the magic\n rawData *base = &knotenext[0];\n *base = knoten[0];\n\n cout << knotenext[0].x << endl;\n cout << knotenext[0].a << endl;\n\n delete[] knoten;\n delete[] knotenext;\n\n return 0;\n}\n<\/code><\/p>\n Ausgabe:<\/p>\n 1 Valgrind:<\/p>\n kater@mintux:~$ valgrind .\/a.out --leak-check=full Eigentlich h\u00e4tte ich erwartet, dass man das alte Basisobjekt noch l\u00f6schen muss. Aber anscheinend nicht :)<\/p>\n","protected":false},"excerpt":{"rendered":" Man hat ein Array von Objekten einer abgeleiteten Klasse. Da new[] nur den Default Konstruktor aufruft, kann man keine schon existierende Instanz der Basisklasse mitgeben. Folgender Code zeigt, wie man die Basisinstnaz nachtr\u00e4glich \u00e4ndern kann. \/\/ example to change the base instance of a derived object #include < iostream > using namespace std; class rawData […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[14,17,33],"class_list":["post-901","post","type-post","status-publish","format-standard","hentry","category-allgemein","tag-c","tag-cpp","tag-tuning"],"_links":{"self":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/901","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=901"}],"version-history":[{"count":5,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/901\/revisions"}],"predecessor-version":[{"id":1528,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/901\/revisions\/1528"}],"wp:attachment":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=901"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=901"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=901"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n\/\/ example to change the base instance of a derived object
\n#include < iostream >
\nusing namespace std;<\/p>\n
\n{
\npublic:
\n double x;
\n};<\/p>\n
\n{
\npublic:
\n int a;
\n};<\/p>\n
\n{
\n rawData *knoten = new rawData[2];
\n knoten[0].x = 0;<\/p>\n
\n knotenext[0].x = 1;
\n knotenext[0].a = 10;<\/p>\n
\n10
\n0
\n10\n<\/p><\/blockquote>\n
\n==7218== Memcheck, a memory error detector.
\n==7218== Copyright (C) 2002-2007, and GNU GPL'd, by Julian Seward et al.
\n==7218== Using LibVEX rev 1854, a library for dynamic binary translation.
\n==7218== Copyright (C) 2004-2007, and GNU GPL'd, by OpenWorks LLP.
\n==7218== Using valgrind-3.3.1-Debian, a dynamic binary instrumentation framework.
\n==7218== Copyright (C) 2000-2007, and GNU GPL'd, by Julian Seward et al.
\n==7218== For more details, rerun with: -v
\n==7218==
\n1
\n10
\n0
\n10
\n==7218==
\n==7218== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 18 from 1)
\n==7218== malloc\/free: in use at exit: 0 bytes in 0 blocks.
\n==7218== malloc\/free: 2 allocs, 2 frees, 40 bytes allocated.
\n==7218== For counts of detected errors, rerun with: -v
\n==7218== All heap blocks were freed -- no leaks are possible.\n<\/p><\/blockquote>\n