Type safety means that the compiler will validate types while compiling, and throw an error if you try to assign the wrong type to a variable.<\/p>\n
Some simple examples:<\/p>\n
\/\/ Fails, Trying to put an integer in a string\nString one = 1;\n\/\/ Also fails.\nint foo = \"bar\";\n<\/code><\/pre>\nThis also applies to method arguments, since you are passing explicit types to them:<\/p>\n
int AddTwoNumbers(int a, int b)\n{\n return a + b;\n}\n<\/code><\/pre>\nIf I tried to call that using:<\/p>\n
int Sum = AddTwoNumbers(5, \"5\");\n<\/code><\/pre>\nThe compiler would throw an error, because I am passing a string (“5”), and it is expecting an integer.<\/p>\n
In a loosely typed language, such as javascript, I can do the following:<\/p>\n
function AddTwoNumbers(a, b)\n{\n return a + b;\n}\n<\/code><\/pre>\nif I call it like this:<\/p>\n
Sum = AddTwoNumbers(5, \"5\");\n<\/code><\/pre>\nJavascript automaticly converts the 5 to a string, and returns “55”. This is due to javascript using the + sign for string concatenation. To make it type-aware, you would need to do something like:<\/p>\n
function AddTwoNumbers(a, b)\n{\n return Number(a) + Number(b);\n}\n<\/code><\/pre>\nOr, possibly:<\/p>\n
function AddOnlyTwoNumbers(a, b)\n{\n if (isNaN(a) || isNaN(b))\n return false;\n return Number(a) + Number(b);\n}\n<\/code><\/pre>\nif I call it like this:<\/p>\n
Sum = AddTwoNumbers(5, \" dogs\");\n<\/code><\/pre>\nJavascript automatically converts the 5 to a string, and appends them, to return “5 dogs”.<\/p>\n
Not all dynamic languages are as forgiving as javascript (In fact a dynamic language does not implicity imply a loose typed language (see Python)), some of them will actually give you a runtime error on invalid type casting.<\/p>\n
While its convenient, it opens you up to a lot of errors that can be easily missed, and only identified by testing the running program. Personally, I prefer to have my compiler tell me if I made that mistake.<\/p>\n
Now, back to C#…<\/p>\n
C# supports a language feature called covariance, this basically means that you can substitute a base type for a child type and not cause an error, for example:<\/p>\n
public class Foo : Bar\n {\n }\n<\/code><\/pre>\nHere, I created a new class (Foo) that subclasses Bar. I can now create a method:<\/p>\n
void DoSomething(Bar myBar)\n<\/code><\/pre>\nAnd call it using either a Foo, or a Bar as an argument, both will work without causing an error. This works because C# knows that any child class of Bar will implement the interface of Bar.<\/p>\n
However, you cannot do the inverse:<\/p>\n
void DoSomething(Foo myFoo)\n<\/code><\/pre>\nIn this situation, I cannot pass Bar to this method, because the compiler does not know that Bar implements Foo’s interface. This is because a child class can (and usually will) be much different than the parent class.<\/p>\n
Of course, now I’ve gone way off the deep end and beyond the scope of the original question, but its all good stuff to know \ud83d\ude42<\/p>\n
Originally posted 2013-11-09 23:23:02. <\/small><\/p>","protected":false},"excerpt":{"rendered":"
Type safety means that the compiler will validate types while compiling, and throw an error if you try to assign the wrong type to a variable. Some simple examples: \/\/ Fails, Trying to put an integer in a string String one = 1; \/\/ Also fails. int foo = “bar”; This also applies to method […]<\/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-1093","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/1093","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=1093"}],"version-history":[{"count":0,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/1093\/revisions"}],"wp:attachment":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/media?parent=1093"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/categories?post=1093"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/tags?post=1093"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}