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问题 class car { int speed; double position; public: car(int v,double d); int getspeed(); }; int car::getspeed() { return speed; } car::car(int s, double x){ speed=s; position=x; } Even though i specified different variables for car(int s,v), why does it work? i though it should give me a compile time error? this code:which var it uses? class car { int speed; double position; public: car(int speed,double time); int getspeed(); }; int car::getspeed() { return speed; } car::car(int speed, double

问题 I'm pretty new to this, so I'm sorry if I screw up any of the lingo. Thanks a bunch for anybody's help or thoughts. I have the following wrong code: Sub ExampleSub(text As String) ClassObject." & text & "_attribute = 1 End Sub So if I call ExampleSub("cheese"), I would like it to set ClassObject.cheese_attribute equal to 1. Any thoughts? I'm not even sure it's possible. Thanks so much! 回答1: Here is another method that might work. Use a scripting dictionary object as one of the classobject's

问题 i have an issue doing toggleClass it doesn't seem to work properly. the image should change in between show and hide . It does change in to hide , but no back here is my example and some code: <div class="top_menu_hidden" style="display: none; ">testing</div> <div class="show_menu"></div> $('.show_menu').on('click', function(){ $('.top_menu_hidden').stop().slideToggle('normal', function(){ $(".show_menu").toggleClass("hide_menu show_menu"); }); });​ .show_menu{ background: url("http:/

问题 I have a template base class.Lets say. template<class KeyF> class Base { private: int member1; char member2; .... }; I derived another class from above class. template<class KeyF> class Derived : public Base<KeyF> { public: void func1() { <accessing member1/member2> } .... }; Above code doesn't compile in gcc. saying that member1 is not a member of Derived. But it is already derived from a Base Class, then why can't it access its member? 回答1: Members in Base are private . You cannot access

问题 what is difference between following variable usages public class A{ B b= new B(); public void doSomething() { b.callme(); } } VS public class A { B b; public void doSomething() { b=new B(); b.callme(); } } if we have single "b" inside a class then which one is better practice and why. and under what circumstances one whould be used. 回答1: These actually have very different meanings. In case 1, the b object is assigned when A is constructed. It is constructed once and only once (unless you are

问题 Here is the code: interface hi { public void meth1(); } abstract class Hullo { public abstract void meth1(); } public class Hello extends Hullo implements hi { public void meth1(){} } Question:The code compiles and everything. I wanted to know the meth1() in class Hello is overriding which meth1()? The ont in the interface or the one in the abstract class and why? 回答1: The answer is short: Both..... In fact, to be correct: You are overriding none of them, you are implementing them both, with

问题 I'm find I have several places that having public static inner classes designed that extend "helper" classes makes my code a lot more type safe and, in my opinion, readable. For example, imagine I have a "SearchCriteria" class. There are a lot of commonalities for the different things I search for (a search term and then a group of search term types, a date range, etc.) By extending it in a static inner class, I tightly couple the extension and the searchable class with the specific

问题 I'm find I have several places that having public static inner classes designed that extend "helper" classes makes my code a lot more type safe and, in my opinion, readable. For example, imagine I have a "SearchCriteria" class. There are a lot of commonalities for the different things I search for (a search term and then a group of search term types, a date range, etc.) By extending it in a static inner class, I tightly couple the extension and the searchable class with the specific

问题 I have a string, containing an Class name. It is, for example, a string containing "Article". That string came up from the params[]. What should I do to work with this string as if it was a class name? For instance, I want to do: Article.all and so on. Any idea? 回答1: This solution is better than eval as you are evaluating params hash that might be manipulated by the user and could contain harmful actions. As a general rule: Never evaluate user input directly, that's a big security hole. #

问题 This question already has answers here : What does ** (double star/asterisk) and * (star/asterisk) do for parameters? (20 answers) Closed 4 years ago . I'm passing a lot data around; specifically, I'm trying to pass the output of a function into a class and the output contains a tuple with three variables. I can't directly pass the output from my function (the tuple) into the class as in the input parameters. How can format the tuple so it is accepted by the class without input_tuple[0],