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1. Top results related to what are the function of dictionary in c code that allows

   • What are the benefits of function pointers in C?

     Top Answer

     Answered Jul 19, 2017 · 3 votes

     • Same as regular typdefs, incredibly useful for 2 and 4. Instead of typing the whole thing, you can now use myFuncDef
     • A function declaration for a function that recieves a function pointer. A function that takes a function pointer of 1. would thus look int add2to3(myFuncDef functionPtr);
     • -
     • A function that takes an int and (probably based on that) returns you a function pointer. Using the typedef it would have looked like myFuncDef functionFactory(int n);

     Without typedefs these chains of pointers to pointers could get incredibly long as can be seen in this question: C syntax for functions returning function pointers

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     1/5

   • What are the pros and cons of using extern variables in C in production code?

     Top Answer

     Answered Jul 11, 2019 · 6 votes

     One can share a variable between files in (at least) four ways. You already mentioned two of them:

     • using extern: it will be a global variable, anyone will be able to modify it, not thread-safe; the use of global variables should be minimized;
     • passing a pointer to the the variable: it will provide read / write access to the variable;
     • passing the value of the variable: provides read-only access to the variable;
     • using an access function.

     The function can be as simple as:

     float read_speed(){ return speed;}-

     If the variable needs to be modified also, another function can be provided:

     void write_speed(float new_speed){ speed = new_speed;}-

     The advantage of using access functions is that it separates the variable from the other files. If needed, you can provide several functions for the same variable, for different needs.

     The cost is that code will increase a little and speed will decrease lightly.

     Compare:

     float read_speed_mph(); // get speed in miles per hourfloat read_speed_mps(); // get speed in meters per second-

     They both return the same speed, expressed in different units. The body of the functions will make the right calculation to provide the correct value, while the variable will remain unmodified.

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     2/5

   • What are the principles of organizing C++ code in Visual Studio?

     Top Answer

     Answered Feb 09, 2016 · 1 votes

     The basic rule is: A project results in a single output file [1].

     If you want to package building blocks into static libraries, create a project for each one.

     Unit test are separate from the code, so it's common to see a "foo" and a "foo test" project side by side.

     With respect to your small building blocks, I use this guideline: If it is closely enough related to be put in the same folder, it is closely enough related to be put in the same project.

     And managing a ton of small projects is incredibly frustrating. They each have a million settings and definitions (under multiple configurations and platforms...) that are a real pain to transfer from one project to the other.

     Property pages are intended to solve this problem. Just define a property page containing related settings and definitions, and it becomes as easy as adding the property page to a new project.

     As each project can pull its settings from multiple property pages, you can group them into logical groups. As an example: a "unit test" property page with all settings related to your unit test framework.

     To create property page in Visual Studio 2015: in the View menu, there is an option "Property Manager". You get a different tree view of your solution, with the projects, then the configurations, and then all the property pages for that project+configuration combination. The context menu for the configuration has an option to create a new property page or to add an existing one.

     [1] Although it is common to have the Release configuration result in foo.dll and Debug configuration in food.dll, so they can exist next to each other without resorting to the Debug/ and Release/ folders. In the General properties, set the TargetName to "$(ProjectName)d" (for Debug configuration) and remove the "$(Configuration)" from the OutputDirectory (for all configurations) to achieve this.

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     3/5

   • What are the semantics of function pointers with empty parentheses in each C standard?

     Top Answer

     Answered Mar 25, 2018 · 2 votes

     N1570 6.11.6:

     The use of function declarators with empty parentheses (not prototype-format parameter type declarators) is an obsolescent feature.

     This same wording appears in the 1990, 1999, and 2011 editions of the ISO C standard. There has been no change. The word obsolescent says that the feature may be removed in a future edition of the Standard, but so far the committee has not done so. (Function pointer declarations are just one of several contexts where function declarators can appear.)

     The Introduction section of the C standard explains what obsolescent means:

     Certain features are obsolescent, which means that they may be considered for withdrawal in future revisions of this International Standard. They are retained because of their widespread use, but their use in new implementations (for implementation features) or new programs (for language [6.11] or library features [7.31]) is discouraged.

     A call to a function declared with an old-style declarator is still required to pass the correct number and type(s) of arguments (after promotion) as defined by the function's actual definition. A call with incorrect arguments has undefined behavior, which means that the compiler is not required to diagnose the error; the burden is entirely on the programmer.

     This is why prototypes were introduced, so that the compiler could check correctness of arguments.

     On an i386 system with GCC, “extra” arguments passed in a call to an empty-parentheses-type’d function pointer are ignored, because of how stack frames work ...

     Yes, that's well within the bounds of undefined behavior. The worst symptom of undefined behavior is having the program work exactly as you expect it to. It means that you have a bug that hasn't exhibited itself yet, and it will be difficult to track it down.

     You should not depend on that unless you have a very good reason to do so.

     If you change

     int (*fp)() = foo;-

     to

     int (*fp)(int) = foo;-

     the compiler will diagnose the incorrect call.

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     4/5

   • What are the different between calling constructor and calling function pointer of constructor in C++

     Top Answer

     Answered Jan 28, 2024 · 0 votes

     Calling a constructor and calling a function pointer of a constructor in C++ are very similar in the sense that they are both quite impossible:

     • You cannot call a constructor in C++.
     • You cannot obtain a pointer to a constructor in C++.

     According to the C++ spec about constructors:

     Constructors have no names and cannot be called directly.

     So, in C++, you do not call constructors. The language does that for you when you use the new keyword, when you declare an object on the stack, etc. The expression new MyClass() might look like a constructor invocation, and it does in fact contain a constructor invocation, and so it might be mistaken for a constructor invocation, but that's not what it is; it is a "new expression", which includes, among other things, an invocation of a constructor. But the other things are crucial: you cannot just skip them and directly invoke the constructor.

     Function pointers of constructors do not exist because normally you cannot take the address of a constructor. If you examine the names exported by the DLL, and somehow figure out which name corresponds to the constructor, and use that name to obtain the entry point of that constructor from the DLL, you are cheating: you are doing something which is not normally supported by the language. As a result, you should not attempt to invoke that entry point. A constructor is only supposed to be invoked by the language.

     Also according to the C++ spec:

     A constructor is a special non-static member function of a class.

     (Emphasis mine.)

     A constructor assumes that memory has been allocated, and proceeds to initialize that memory. The language takes care of the memory allocation, but invoking the constructor directly does not. Since a constructor is non-static, it expects an uninitialized this to be passed to it, but you are not allocating any memory and you are not passing anything to the constructor. The result is exactly as expected: a crash.

     And besides, think about it: the constructor could not be internally allocating the memory, because how would it work then if the object was allocated on the stack? And how would it work if the constructor was being invoked by the constructor of a derived class which presumably occupies more memory?

     You can get your DLL to work by using a factory method. A factory method is a public static method which executes new ClassA() and returns the result, or declares ClassA() and returns it by value. Then, obtain the address of the factory method from the DLL, and invoke it.

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2. stackoverflow.com › questions › 4384359data structures - Quick Way to Implement Dictionary in C ...

   stackoverflow.com › questions › 4384359

   • Cached

   Section 6.6 of The C Programming Language presents a simple dictionary (hashtable) data structure. I don't think a useful dictionary implementation could get any simpler than this. For your convenience, I reproduce the code here. struct nlist { /* table entry: */. struct nlist *next; /* next entry in chain */. char *name; /* defined name */.

   Code sample

   struct nlist {

     struct nlist *next;

     char *name;

     char *defn;

   };...

   See more on stackoverflow

3. www.geeksforgeeks.org › implementation-on-map-orImplementation on Map or Dictionary Data Structure in C

   www.geeksforgeeks.org › implementation-on-map-or

   • Cached

   Mar 27, 2023 · Functions used to implement Map in C. The getIndex function searches for a key in the keys array and returns its index if found, or -1 if not found. The insert function inserts a key-value pair into the map. If the key already exists, it updates the value. The get function returns the value of a key in the map, or -1 if the key is not found.

4. People also ask

   Can I create a dictionary in C?

   • You can create anything you want in C. You just won't have native language support for most of it. You can create a dictionary in C, but there is no dictionary built in to the standard C library. A quick search on Google code shows that there are open-source (and generously licensed) C dictionary implementations here and here.

   Do dictionaries exist in C? - Stack Overflow

   stackoverflow.com/questions/9405303/do-dictionaries-exist-in-c

   See all results for this question

   Where can a function be defined in C?

   • In C, a function can be defined anywhere in the program, as long as it is defined before it is used. But it is a good practice to define functions at the beginning of the file or in a separate file to make the code more readable and organized. Here's an example code showing how to define a function in C:

   How to Use Functions in C - Explained With Examples - freeCodeCamp.…

   www.freecodecamp.org/news/how-to-use-functions-in-c/

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   What is a function declaration in C?

   • Declaring a function in C informs the compiler about the presence of a function without giving implementation details. This enables the function to be called by other sections of the software before it is specified or implemented. A function declaration usually contains the function name, return type, and the parameter types.

   How to Use Functions in C - Explained With Examples - freeCodeCamp.…

   www.freecodecamp.org/news/how-to-use-functions-in-c/

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   How do I create a dictionary?

   • Each dictionary has space for 1000 elements. You need add the files dic.c and dic.h in your project directory. After that you include dic.h create_dict: is a simple constructor for creating a dictionary and setting up the member field 'number_of_elements' and prepares the inner array 'elements'

   Algorithms_in_C: Dictionary

   thealgorithms.github.io/C/d1/d52/md_data__structures_2dictionary_2_r_e_a_d_m_e.html

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5. thealgorithms.github.io › C › d1Algorithms_in_C: Dictionary

   thealgorithms.github.io › C › d1

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   Overview about functions. c. Dictionary * create_dict (void); create_dict: is a simple constructor for creating a dictionary and setting up the member field 'number_of_elements' and prepares the inner array 'elements'. c. int add_item_label (Dictionary *,char label [],void *); add_item_label: adds item (void*) to the dictionary at given label ...

6. www.freecodecamp.org › news › how-to-use-functions-in-cHow to Use Functions in C - Explained With Examples

   www.freecodecamp.org › news › how-to-use-functions-in-c

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   Apr 6, 2023 · In this approach, the function declaration (or prototype) is included in the header file math.h, which is then included in the main file main.c using the #include directive. The function implementation is defined in a separate file math.c. This approach allows for better code organization and modularity, as the function implementation can be ...

7. www.freecodecamp.org › news › the-c-programmingThe C Programming Handbook for Beginners - freeCodeCamp.org

   www.freecodecamp.org › news › the-c-programming

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   Aug 29, 2023 · To get started, open Visual Studio Code and create a new folder for your C program by navigating to "File" -> "Open" -> "New Folder". Give this folder a name, for example, c-practice, and then select "Create" -> “Open". You should now have the c-practice folder open in Visual Studio Code.

8. users.cs.utah.edu › C_Language › c_functionsC Programming - Functions - University of Utah

   users.cs.utah.edu › C_Language › c_functions

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   C Programming - Functions. Functions in the C programming Language. The C language is similar to most modern programming languages in that it allows the use of functions, self contained "modules" of code that take inputs, do a computation, and produce outputs. C functions must be TYPED (the return type and the type of all parameters specified).

9. www.cs.uic.edu › C_Programming › FunctionsC Programming Course Notes - Functions

   www.cs.uic.edu › C_Programming › Functions

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   Function prototypes are often placed in separate header files, which are then included in the routines which need them. For example, "math.h" includes the function prototypes for the C math functions sqrt( ) and cos( ). Exercise: Write function prototypes for: A function which takes an int and a float, and returns a double.