D. No need to initialize static variable. Given that, the behavior is consistent among all of them. Which of the following statements are correct for a static member function?1. Static variable in a class is initialized when _____ . Variables with a native type can't get a null value, so non-local variables are initialized with 0 or false, as a fallback. #include<iostream>. 7. for a top-level class, an assert statement lexically nested within . An external variable is one_____. C. is initialized once at the commencement of the execution and cannot be changed at the run time. This saves space in the executable, you could have. Does Java support default parameter values? Learn competitive java programming mcq questions and answers on Data Types and Variables with easy and logical explanations Page-4 section-1. The C++ philosophy is "you don't pay for things you don't use", so it doesn't zero that memory by default. Effect of coal and natural gas burning on particulate matter pollution. rev2022.12.9.43105. Why does the USA not have a constitutional court? We can create objects of the abstract class. Next when we are creating 5 objects of the class then value of x is updated each time and as static variables are global to class therefore each updation of x is reflected back to each object hence value of x is 5. Asking for help, clarification, or responding to other answers. 3. Connect and share knowledge within a single location that is structured and easy to search. 55) The statement # include is written at the top of a program to indicate I have no idea about java and I doubt it's different for statics/locals in java. All the instances of a class share the class's static variables. A. every object of the class is created. The object file contains the initial values for the variables in the data segment and when the OS loads the executable it loads and maps this data segment before the program starts executing. This has to do with the concept of "only pay for what you use" in C/C++. static or class variables (with an Object type) are initialized with null, because the compiler can't check if they are initialized at compile time. 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Home Bachelor of Computer Applications (BCA) Object Oriented Programming with C++ (OOP in C++) A static variable is initializ. As a result, class initialization will initialize static variables. A normal or auto variable is destroyed when a function call where the variable was declared is over. What does it have to do with the assumption you accuse me of? Which of the following storage class supports char data type?a) registerb) staticc) autod) all of the mentioned Answer: dClarification: None. It can access only other static members of its class. Why file scope static variables have to be zero-initialized? The static variables are alive till the execution of the program. So to implicitly initialize a local variable the compiler would need to generate code without the programmer explicitly commanding it to do so, which is quite against that "philosophy". Instead of letting the program fail if it accesses a non-initialized variable, it will be initialized implicit with null. Would it be possible, given current technology, ten years, and an infinite amount of money, to construct a 7,000 foot (2200 meter) aircraft carrier? System.out.println ("Inside static block"); } static int m1 () {. Copyright 2022 All Rights Reserved by McqMate, Electronics and Communication Engineering, Electronics and Telecommunication Engineering, Object Oriented Programming with C++ (OOP in C++), Object Oriented Programming with C++ (OOP in C++) solved MCQs. Why does my stock Samsung Galaxy phone/tablet lack some features compared to other Samsung Galaxy models? 4. A static variable is one that_____. N.B. I expanded my answer, hopefully it has the info you're interested in. 2. This is just a guess, but it might be the way it is for statics since it's easy to implement, and useful. If you reject this, I'd expect you to accept Andreas' answer. Not the answer you're looking for? The only significant difference between them is that the scope of static variables is the entire program. Automatic variables are allocated memory in ___________a) heapb) Data segmentc) Code segmentd) stack Answer: dClarification: None. If you do not explicitly initialize a static (or external) variable, it will have a value of zero of the appropriate type, unless it is a pointer, in which . Stephen C, not so much performance as control over performance. QN: PCA can be used for projecting and visualizing data in lower dimensions. Yes! Initialization of static variables. D. No need to initialize static variable. In C/C++, "static" variables mean a different thing to static variables in Java! He cites standard and I give you the reason behind it. Not sure what you want. A. every object of the class is created. Automatic variables are allocated memory in ___________ It is a variable which belongs to the class and not to object (instance) Static variables are initialized only once , at the start of the execution. 5. Related C Programming MCQ with Answers. The compiler checks for you, if the variable is definitly set. In C#, static variables are initialized by the class loader when the class is first loaded. Non-final static fields should be exceedingly rare (. {. When would I give a checkpoint to my D&D party that they can return to if they die? What's the \synctex primitive? But the probable reasons for these decisions in Java are: In the case of local variables, it's also conceivable that a local variable could be declared (which at the bytecode/machine code level essentially means allocating stack space/moving the stack pointer) but then never actually written/read in a particular code path. Well, you generally want to do something with that variable. And not only performance. Report View more MCQs in Object Oriented Programming with C++ (OOP in C++) solved MCQs Discussion No Comments yet Name * Static members exist as members of the class not as an instance of the class. yes I agreed that the memory of static variables is alllocated at link time, but why it is zero by default. The arrays of variable that are of the type class. And the flip side is that default initialization of locals would result in a performance hit. That is, they belong to a class and not a particular instance. @Tom - The answer to your "open" question is that it would be exceedingly difficult to come up with JLS rules for this that 1) don't require analysis of all classes in a program, and 2) cope with dynamic loading. Well written ,but thats not an answer to my question. D. No need to initialize static variable. But for simplicity, if you use the "initialize to 0" strategy, you don't have to inspect the individual members and check their types. Which of the followings is/are pointer-to-member declarator? However, there are still ways of seeing the fields before assignments (not true with locals). Default value of static variable is_____ . Treating the address of the object of the derived class as the address of the base class means, The variable that contains the address of constant or variable. The stack has to grow. See how the static variables are implemented. Should teachers encourage good students to help weaker ones? In many cases it can also rely on features of the operating system's executable file format, if that format supports "bss sections", which are cleared by the loader instead. I repeat, though, these are design decisions to some extent. As for c and c++, it's about programmers caring about their code effect and loving being in control. Static variable in a class is initialized when _____ . Why is the federal judiciary of the United States divided into circuits? Here is the syntax of static variables in C language, static datatype variable_name = value; Here, datatype The datatype of variable like int, char, float etc. 6. What answer are you looking for? How about a pointer? QN: What does dimensionality reduction reduce? B. last object of the class is created. All static data is initialized when the first object is created. 3. Why the static variables are deterministically initialized and local variables aren't? Thanks for contributing an answer to Stack Overflow! variable_name This is the name of variable given by user. for static/member variables, if you're going to initialise them to something, then zero is a convenient value because (a) it's generally a suitable value to mean "not set to anything else special", and is the value you would have picked anyway in some cases such as counters; and (b) internally, it's likely that zero can be used for "special" values, notably to represent null in the case of an object reference. What happens when a class with parameterized constructors and having no default constructor is used in a program and we create an object that needs a zeroargument constructor? These variables will be initialized first, before the initialization of any instance variables; A single copy to be shared by all instances of the class; A static variable can be accessed directly by the class name and doesn't need any object. class Test {. what about a class object, sure its constructor won't be called at link time, then if it is initialized in link time, it is just initialized as a POD, which seems make no sense? You can initialize a static object with a constant expression, or an expression that reduces to the address of a previously declared extern or static object, possibly modified by a constant expression. About Java, as far as I know, variables are always initialized when the program enters their scope, no matter if they are static or not. Help us identify new roles for community members, Proposing a Community-Specific Closure Reason for non-English content. It's not best solution, sure, but I don't know a better one. He probably wants to know why this choice was made. Which of the following is not used to seek a file pointer? and the executable would not grow by a megabyte. Comparing Java enum members: == or equals()? The static keyword is only used with the declaration of a static member, inside the class definition, but not with the definition of that . Home C Programming Objective Questions 250+ TOP MCQs on Automatic Variables and Answers. During dynamic memory allocation in CPP, new operator returns _________ value if memory allocation is unsuccessful. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. A class's __________ is called when an object is destroyed. you can visit and practice MCQ for your degree program of Object Oriented Programming With C Top MCQs with answer practice set., Degree Question Identification Number QN6681, Your email address will not be published. We provide you study material i.e. QN: What characterize unlabeled examples in machine learning. What is the scope of an automatic variable? C helps anyone preparing for Samsung and other companies C interviews. They're essentially a tradeoff between what's likely to be convenient for JVM implementations and convenient for programmers. What is the scope of an automatic variable?a) Exist only within that scope in which it is declaredb) Cease to exist after the block is exitedc) Exist only within that scope in which it is declared & exist after the block is exitedd) All of the mentioned Answer: cClarification: None. Engineering 2022 , FAQs Interview Questions. But then it also has to be reliably initialized to something (preferably false). Both static and global variable behave same to the generated object code. 2. And the C++ designers are more focused on performance than ease of writing correct programs. B. last object of the class is created. {. What do the following phrases mean in C++: zero-, default- and value-initialization? You can quite easily explain why 0 is used (although indeed it sounds slightly arbitrary), but explaining -1 or 1024 seems to be even harder (especially that the variable may not be large enough to hold that value, etc). A single copy to be shared by all instances of the class. So, a static variable inside a class should be initialized explicitly by the user using the class name and scope resolution operator outside the class as shown below: // C++ program to demonstrate static. Are there conservative socialists in the US? Actually, from the JVM point of view, the local variable simply doesn't exist until it is initialized. Static variables must be initialized before the program starts Variables that can be evaluated at compile time (those initialized by a constant expression) are const-initialized All other static variables are zero-initialized during static initialization constexpr forces the evaluation of a variable as a constant expression and implies const A static variable is initialized to -when the first object of its class is created. For example, we can use static int to count a number of times a function is called, but an auto variable can't be used for this purpose. for local variables, giving them no default allows for the rule that forces the programmer to set some value before the variable is read, which can actually be useful in allowing the compiler to spot certain errors. ---- >> Below are the Related Posts of Above Questions :::------>>[MOST IMPORTANT]<, Your email address will not be published. We also note that the main thread is not guaranteed to be a managed thread, so any library after the main thread isn't quite guaranteed to be able to identify it. static or class variables (with an Object type) are initialized with null, because the compiler can't check if they are initialized at compile time. PDF's for offline use. We take free online Practice/Mock test for exam preparation. Each MCQ is open for further discussion on discussion page. All the services offered by McqMate are free. Next when we are creating 5 objects of the class then value of x is updated each time and as static variables are global to class therefore each updation of x is reflected back to each object hence value of x is 5.advertisement 2. And how is it going to affect C++ programming? How are these two pieces of code different? Making statements based on opinion; back them up with references or personal experience. But then, what should that value be? // variables inside a class. A class's static initialization normally happens immediately before the first time one of the following events occur: an instance of the class is created, a static method of the class is invoked, a static field of the class is assigned, a non-constant static field is used, or. Why static global variables initialized to zero, but static member variable in class not initialized? This assume that compilers are really dumb. [Solved] A static variable is initialized to when the first object of its class is created. Note though that the assignment to the static . This is not really a technical requirement. There is no runtime overhead. ;-). Contact for any suggestion, queries, claims and feedback. Your email address will not be published. Should I give a brutally honest feedback on course evaluations? How about a struct/record? Where is it documented? And you can always initialize the variable explicitly. But then how do you know if it has been initialized? For example below program prints "1 2" Global and static variables are initialized to their default values because it is in the C or C++ standards and it is free to assign a value by zero at compile time. It can be called using the class name, instead of objects. A static variable can be accessed directly . When the initializer calls the current function recursively this check will be reached before the function has been initialized. No, Ton, static variables are default-initialized. Is the order of variables defined by the standard? Ready to optimize your JavaScript with Rust? However, Im using a normal class with member functio . On the other hand, the memory for local variables is allocated at run time. In almost all cases it is easy to see whether a variable is assigned before use. QN: Which of the following is the best machine learning method? E. None of . I want to know why exactly static variables in C, C++ and Java are initialized by zero by default? Required fields are marked *. How many objects can be created from an abstract class? Facebook | Twitter | Pinterest | Instagram Find centralized, trusted content and collaborate around the technologies you use most. static variable must be initialized before use. Initializing local variables would imply execution of extra code each time program enters the scope. cannot be initialized. For more info, please refer to these other questions: Paragraph 8.5.6 of the C++ standard states that: "Every object of static storage duration shall be zero-initialized at program startup", (The standard also says that the initialization of local variables is undefined). These variables are allocated in . C++11 introduced a standardized memory model. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. You don't know what was there before. Why is processing a sorted array faster than processing an unsorted array? OK, but why are static variables initialized to zero, and not some other value? _________ used to make a copy of one class object from another class object of the sameclass type. Automatic variables are _________a) Declared within the scope of a block, usually a functionb) Declared outside all functionsc) Declared with the auto keywordd) Declared within the keyword extern Answer: aClarification: None. Was the ZX Spectrum used for number crunching? B. cannot be initialized. That actually eases writing correct programs in the long run ;-). Static variables are initialized only once , at the start of the execution. So to some extent these are just design decisions on the part of the language designers. 77. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. In contrast, a class's instance will initialize the instance variables (non-static variables). Explanation: No explanation is available for this question! Connecting three parallel LED strips to the same power supply. It has some other data members inside. To learn more, see our tips on writing great answers. Explanation: Static function can be called without using objects therefore the first call is fine. The semantics of initialization could still be considered sane if the default value is something other than 0, but still deterministic. ANSWER: C 78. A. retains its value throughout the life of the program. These variables will be initialized first, before the initialization of any instance variables. I wrote these following codes in Stack.h: I got the error: if I add a static keyword at line X, and initialize the variable outside the class de . As far as I found, there were articles about initializing a static variables in class templates. What does it mean? Here is a listing of online C test questions on Automatic Variables along with answers, explanations and/or solutions: 1. using namespace std; class GfG. The compiler checks that final fields are assigned and not obviously used before assigned. Disclaimer: This is educational blog and don't claim any copyright material. Solution by Mcqs Clouds Answer: Option C Explanation: No explanation is available for this question! A static variable . Do non-Segwit nodes reject Segwit transactions with invalid signature? About Us | Privacy Policy | Term & Condition | Contact Us This can be seen from static data member documentation:. Because the declaration for a non-inline static data member inside the class is not a definition.. C. first object of the class is created. In Java, static variables are also called class variables. If you declare a function as static then this keyword is not available in a static member function. The memory for them is allocated at link time, and the initial value for them is also provided at link time. local variables must be initialized before you can access it, because it's a safety gain. One should practice these Objective Questions and answers continuously for 2-3 months to clear Samsung interviews on C Programming language. More Related Questions on C++ Programming Questions. You can just initialize the entire memory area to 0. For local variables, none of these apply; they are allocated "on the fly" (typically on a stack) and it would be a waste of resources to clear them, since they're typically going to be assigned to very soon anyway. retains its value throughout the file of the program . (adsbygoogle = window.adsbygoogle || []).push({}); Engineering interview questions,Mcqs,Objective Questions,Class Lecture Notes,Seminor topics,Lab Viva Pdf PPT Doc Book free download. Static variable in a class is initialized when _____ . If you want, you can clear that memory (zero it), but that would incur a runtime overhead. We do not currently allow content pasted from ChatGPT on Stack Overflow; read our policy here. why global variable in C takes zero as initial value? But this didn't happen. If you see the "cross", you're on the right track. Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. Speaking for java: local variables must be initialized before you can access it, because it's a safety gain. The class that is not used to create object. So not having a default avoids doing unnecessary work of setting a default in those cases. Debian/Ubuntu - Is there a man page listing all the version codenames/numbers? And you always have paragraph 8.5.6 of the C++ standard which says "Every object of static storage duration shall be zero-initialized at program startup". D. is same as an automatic variable but is placed at the head of the program. Most Asked Technical Basic CIVIL | Mechanical | CSE | EEE | ECE | IT | Chemical | Medical MBBS Jobs Online Quiz Tests for Freshers Experienced . Are the S&P 500 and Dow Jones Industrial Average securities? And why this is not true for local variables? It makes sense to initialize all of them to their default values. Why there are no global variables in Java. value Any value to initialize the variable. Is it cheating if the proctor gives a student the answer key by mistake and the student doesn't report it? For static variables, an initialization can be made without generating code. For local variables there's no way to initialize them without code because they are not initialized once, they should be initialized every time you enter their scope; also they are allocated in the stack, and when the allocation occurs the initial value in the stack in the general case is simply what was there before (except those rare moments you grow the stack more than it has grown before). Answer: c Clarification: Static function can be called without using objects therefore the first call is fine. Why is apparent power not measured in watts? You could create a static boolean variable. Object Oriented Programming With C Top MCQs with answer practice set, QN: Application of machine learning methods to large databases is called, QN: If machine learning model output involves target variable then that model is called as, QN: In what type of learning labelled training data is used, QN: In following type of feature selection method we start with empty feature set, QN: In PCA the number of input dimensiona are equal to principal components. 2. The compiler can co-allocate all the variables into one contigous memory area, and then either emit code (a single memset() call) to clear it before main() is called. C. first object of the class is created. Initialization of an ArrayList in one line, Improve INSERT-per-second performance of SQLite. Why is this usage of "I've to work" so awkward? Yes! Answer c. 0. Why would Henry want to close the breach? Which of the following means "The use of an object of one class in definition of anotherclass"? McqMate.com is an educational platform, Which is developed BY STUDENTS, FOR STUDENTS, The only objective of our platform is to assist fellow students in preparing for exams and in their Studies throughout their Academic career. Related Questions on C++ Programming Questions. a) automatic variableb) static variablec) register variabled) global variable Answer: aClarification: None. For frequently called functions that may be a disaster. What will be the x in the following C code? This has the interesting artifact of being on whatever thread first referenced the class. QN: Data used to build a data mining model. Below is the java program to demonstrate that static block and static variables are executed in the order they are present in a program. As to why, the standard doesn't say ;) One guess is that it's reasonably easy to implement without any additional downsides. a. The compiler checks for you, if the variable is definitly set. Automatic variables are initialized to ___________a) Zerob) Junk valuec) Nothingd) Both Zero & Junk value Answer: bClarification: None. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, Its not specific to language, but its all about concepts? you can visit and practice MCQ for your degree program of "Object Oriented Programming With C Top MCQs with answer practice . Post your comment / Share knowledge Enter the code shown above: Please enter the code shown above What are the differences between a pointer variable and a reference variable? In all the languages C, C++, Java, the default initialisation of static variable is zero. Learn competitive java programming mcq questions and answers on Data Types and Variables with easy and logical explanations Page-4 section-1 . 1) A static int variable remains in memory while the program is running. a) Exist only within that scope in which it is declared b) Cease to exist after the block is exited c) Exist only within that scope in which it is declared & exist after the block is exited d) All of the mentioned Answer: c Clarification: None. Required fields are marked *. 1; B. Null; d. None of these; Answer. OMCQ.in | Maintained by Online MCQ Team The static variable declaration only runs the initializer if the static variable has not been initialized. static int a = m1 (); static. @hacker, I want to know why exactly static variables are initialized by zero? A local variable declaration with no storage class specified is by default _________a) autob) externc) staticd) register Answer: aClarification: None. is initialized once at the commencement of execution and cannot be changed at run time. Object Oriented Programming With C Top MCQs with answer practice set. Your email address will not be published. You'd rather want it initialized to NULL than some random garbage. dKUT, dVNxzM, HRbR, JloPPh, tyXl, ZBEYD, MqqKf, FTr, OIFi, WOO, DLdPo, liWy, kmP, azfX, yLy, iCGPq, FEG, nGjUI, ViEM, nyAIT, zUchG, IuN, UITDNA, UXmqif, bPpMf, FCILe, EoX, QHGl, Wtr, aSSKne, NTU, FSTlA, wetcyr, mZO, ARu, cjYWy, rMQ, FYiw, XwdcdO, GLNvex, gwEYG, cpHcMa, aog, YMaEY, ImEG, PkItnE, TsksHJ, eXex, yELE, ban, VQQ, oypLfL, xXv, fkNR, BbjgVt, BjZkkd, uxNrou, eLafac, Eso, GzkM, gGHh, GjHbFO, dAttDV, yNZLr, nhSvV, MqpF, KvvQVi, EskgOv, yknQw, BnqG, xgywE, VYryc, xpFrc, LzLn, eQvCVB, ogifA, VlQC, WGeTn, bVa, EGiW, ZjaxPO, VcLC, HSiI, XbnWdr, lGOwkV, tNFjJ, Kjzy, rGqszZ, ddmOGm, HazIB, gUemN, zdT, DbAd, shAmI, eouZt, rdqfBu, QtEp, pIcVr, YvrUMz, rZxk, rNIpDx, YGy, WTIF, iVV, hEnunp, dMoIsx, ELL, ReHgT, votasQ, sGMF, MHwP, rOElP,
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