{"id":4244,"date":"2014-03-30T09:25:29","date_gmt":"2014-03-30T09:25:29","guid":{"rendered":"https:\/\/unknownerror.org\/index.php\/2014\/03\/30\/problem-about-equals-operator-collection-of-common-programming-errors\/"},"modified":"2014-03-30T09:25:29","modified_gmt":"2014-03-30T09:25:29","slug":"problem-about-equals-operator-collection-of-common-programming-errors","status":"publish","type":"post","link":"https:\/\/unknownerror.org\/index.php\/2014\/03\/30\/problem-about-equals-operator-collection-of-common-programming-errors\/","title":{"rendered":"problem about equals-operator-Collection of common programming errors"},"content":{"rendered":"<ul>\n<li><img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/297e728fc79110ee2ea25ccc69a8ffae?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nJon Seigel<br \/>\n.net operators override equals-operator<br \/>\nOr it&#8217;s advisable to do that? Why?<\/li>\n<li><img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/0159784729683001695a04568a4cc236?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nGroo<br \/>\nc# string equals equals-operator<br \/>\nWhat is the difference between == and Equals() with example? I know that == is used to compare operator and Equals() method is used to compare content of string.So i tried\/\/ first example string s1 = &#8220;a&#8221;; string s2 = &#8220;a&#8221;; Console.Write(a.Equals(s2)); \/\/ returns true, but if I assign &#8220;b&#8221; to s2,\/\/ then result will be false\/\/ second example string s1 =&#8221;a&#8221;; string s2 =&#8221;a&#8221;; Console.Write(s1 == s2); \/\/ returns trueHow this is so? Both are different object references. Suppose we consider that these<\/li>\n<li><img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/297e728fc79110ee2ea25ccc69a8ffae?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nJon Seigel<br \/>\nc# operators type-conversion equals-operator<br \/>\nSome code for context: class a {}class b {public a a{get;set;}public static implicit operator a(b b){return b.a;} }a a=null;b b=null;a = b;\/\/compiler: cannot apply operator &#8216;==&#8217; to operands of type tralala&#8230;bool c = a == b;Is it possible to use == operator on different type instances, where one can implicitly convert to another? What did i miss? Edit: If types must be the same calling ==, then why int a=1; double b=1; bool c=a==b;works?<\/li>\n<li><img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/297e728fc79110ee2ea25ccc69a8ffae?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nJon Seigel<br \/>\nc++ operators polymorphism virtual equals-operator<br \/>\nCan someone please put me out of my misery with this? I&#8217;m trying to figure out why a derived operator== never gets called in a loop. To simplify the example, here&#8217;s my Base and Derived class:class Base { \/\/ &#8230; snippedbool operator==( const Base&amp; other ) const { return name_ == other.name_; } };class Derived : public Base { \/\/ &#8230; snippedbool operator==( const Derived&amp; other ) const { return ( static_cast&lt;const Base&amp;&gt;( *this ) ==static_cast&lt;const Base&amp;&gt;( other ) ? age<\/li>\n<li><img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/a7cd283f886e60241d921289f3c83f23?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nMartin<br \/>\nc# java operators equals-operator<br \/>\nin c# what does exactly happen in the background when you do a comparison with the &#8220;==&#8221; operator on two objects? does it just compare the addresses? or does it something like Equals() or CompareTo() ?PS: what about the &#8220;==&#8221; operator in java? does it behave the same?<\/li>\n<li><img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/21ffea7aa8a0cf833901322567c61df9?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nphoog<br \/>\nc# operator-overloading equals-operator<br \/>\nWith code like the followingpublic class Task {string Name;public static bool operator ==(Task t1, Task t2){ return t1.Name = t2.Name &amp;&amp; t1.GetType() == t2.GetType(); } } public class TaskA : Task {int aThing;public static bool operator ==(TaskA t1, TaskA t2){ return (Task)t1 == (Task)t2 &amp;&amp; t1.GetType() == t2.GetType()&amp;&amp; t1.aThing == t2.aThing; } } public class TaskB : Task \/\/more of the sameclass Stuffin {List&lt;Task&gt; Tasks;void CheckIt(){bool theSame = Tasks[0] ==<\/li>\n<li><img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/eebe29db36c8bd272ab59832bc02aeb6?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\ncellige<br \/>\nmysql null operators equals equals-operator<br \/>\nMySql provides a nice operator &lt;=&gt; that works with comparisons that could contain a null such as null &lt;=&gt; null or null &lt;=&gt; 5 etc giving back intuitive results as many programming languages. Where as the normal equals operator always just returns null, which catches many new MySql users such as myself awry.Is there a reason MySql has both and not JUST the functionality in &lt;=&gt; ? Who really needs an operator that is effectively undefined with built in language types?<\/li>\n<li><img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/fc87163df1bb4a74686992ccdfe604df?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nException<br \/>\njavascript equals-operator identity-operator<br \/>\nPossible Duplicate:Javascript === vs == : Does it matter which \u201cequal\u201d operator I use?When would JavaScript == make more sense than ===? What is the difference between below methods in comparing a string with undefined value. var x; if(x==undefined) { alert(x); }and if(x===undefined) { alert(x); }Why should i prefer second method in this case.. Please let me know advantages..<\/li>\n<\/ul>\n<p>Web site is in building<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Jon Seigel .net operators override equals-operator Or it&#8217;s advisable to do that? Why? Groo c# string equals equals-operator What is the difference between == and Equals() with example? I know that == is used to compare operator and Equals() method is used to compare content of string.So i tried\/\/ first example string s1 = &#8220;a&#8221;; [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-4244","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/4244","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/comments?post=4244"}],"version-history":[{"count":0,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/4244\/revisions"}],"wp:attachment":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/media?parent=4244"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/categories?post=4244"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/tags?post=4244"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}