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1. Top results related to what is the difference between c and objective-c?

   • What is the difference between ivars and properties in Objective-C

     Top Answer

     Answered Aug 25, 2017 · 57 votes

     Number 1 differs from the other two by forward declaring the MyOtherObject class to minimize the amount of code seen by the compiler and linker and also potentially avoid circular references. If you do it this way remember to put the #import into the .m file.

     By declaring an @property, (and matching @synthesize in the .m) file, you auto-generate accessor methods with the memory semantics handled how you specify. The rule of thumb for most objects is Retain, but NSStrings, for instance should use Copy. Whereas Singletons and Delegates should usually use Assign. Hand-writing accessors is tedious and error-prone so this saves a lot of typing and dumb bugs.

     Also, declaring a synthesized property lets you call an accessor method using dot notation like this:

     self.otherObj = someOtherNewObject; // set it MyOtherObject *thingee = self.otherObj; // get it -

     Instead of the normal, message-passing way:

     [self setOtherObject:someOtherNewObject]; // set itMyOtherObject *thingee = [self otherObj]; // get it -

     Behind the scenes you're really calling a method that looks like this:

     - (void) setOtherObj:(MyOtherObject *)anOtherObject {- if (otherObject == anOtherObject) { return; }- MyOtherObject *oldOtherObject = otherObject; // keep a reference to the old value for a second otherObject = [anOtherObject retain]; // put the new value in [oldOtherObject release]; // let go of the old object} // set it-

     …or this

     - (MyOtherObject *) otherObject { return otherObject;} // get it-

     Total pain in the butt, right. Now do that for every ivar in the class. If you don't do it exactly right, you get a memory leak. Best to just let the compiler do the work.

     I see that Number 1 doesn't have an ivar. Assuming that's not a typo, it's fine because the @property / @synthesize directives will declare an ivar for you as well, behind the scenes. I believe this is new for Mac OS X - Snow Leopard and iOS4.

     Number 3 does not have those accessors generated so you have to write them yourself. If you want your accessor methods to have side effects, you do your standard memory management dance, as shown above, then do whatever side work you need to, inside the accessor method. If you synthesize a property as well as write your own, then your version has priority.

     Did I cover everything?

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     1/5

   • What is the difference between #import and #include in Objective-C?

     Top Answer

     Answered Sep 27, 2014 · 360 votes

     The #import directive was added to Objective-C as an improved version of #include. Whether or not it's improved, however, is still a matter of debate. #import ensures that a file is only ever included once so that you never have a problem with recursive includes. However, most decent header files protect themselves against this anyway, so it's not really that much of a benefit.

     Basically, it's up to you to decide which you want to use. I tend to #import headers for Objective-C things (like class definitions and such) and #include standard C stuff that I need. For example, one of my source files might look like this:

     #import <Foundation/Foundation.h>-#include <asl.h>#include <mach/mach.h>-

     Other Answers

     Answered Sep 17, 2010 · 387 votes

     There seems to be a lot of confusion regarding the preprocessor.

     What the compiler does when it sees a #include that it replaces that line with the contents of the included files, no questions asked.

     So if you have a file a.h with this contents:

     typedef int my_number;-

     and a file b.c with this content:

     #include "a.h"#include "a.h"-

     the file b.c will be translated by the preprocessor before compilation to

     typedef int my_number;typedef int my_number;-

     which will result in a compiler error, since the type my_number is defined twice. Even though the definition is the same this is not allowed by the C language.

     Since a header often is used in more than one place include guards usually are used in C. This looks like this:

     #ifndef _a_h_included_ #define _a_h_included_- typedef int my_number;- #endif-

     The file b.c still would have the whole contents of the header in it twice after being preprocessed. But the second instance would be ignored since the macro _a_h_included_ would already have been defined.

     This works really well, but has two drawbacks. First of all the include guards have to be written, and the macro name has to be different in every header. And secondly the compiler has still to look for the header file and read it as often as it is included.

     Objective-C has the #import preprocessor instruction (it also can be used for C and C++ code with some compilers and options). This does almost the same as #include, but it also notes internally which file has already been included. The #import line is only replaced by the contents of the named file for the first time it is encountered. Every time after that it is just ignored.

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     Answered Jul 11, 2013 · 70 votes

     I agree with Jason.

     I got caught out doing this:

     #import <sys/time.h> // to use gettimeofday() function#import <time.h> // to use time() function-

     For GNU gcc, it kept complaining that time() function was not defined.

     So then I changed #import to #include and all went ok.

     Reason:

     You #import <sys/time.h>:     <sys/time.h> includes only a part of <time.h> by using #defines

     You #import <time.h>:     No go. Even though only part of <time.h> was already included, as     far as #import is concerned, that file is now already completely included.

     Bottom line:

     C/C++ headers traditionally includes parts of other include files. So for C/C++ headers, use #include. For objc/objc++ headers, use #import.

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     2/5

   • What is the difference between an instance variable/method and a class variable/method in Objective-C?

     Top Answer

     Answered Aug 07, 2010 · 2 votes

     An instance method or variable applies to that instance. A class method (classes in Objective-C don't have variables, though they can be simulated in various ways) applies to the whole class.

     Consider the quintessential Dog class, which derives from the Mammal class (and so on up the tree of life.) A particular dog has a name and a collar and an owner--those are its properties. A particular dog may -bark or -chaseBall or -buryBoneInBackyard--those are its methods.

     The Dog class, on the other hand, has different methods. The Dog class has a +globalPopulation and may instantiate itself with a +dogWithDNA: factory method. The Dog class will have an +isExtinct method indicating whether the species as a whole is extinct (it's not, of course.)

     In short: class methods affect the entire class, while instance methods affect a particular instance of a class.

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     3/5

   • What's the difference between Objective-C and Cocoa?

     Top Answer

     Answered Jan 12, 2009 · 66 votes

     Objective-C is the language... it defines all the things like the keywords for defining objects, the syntax for messaging object, things like that.

     Cocoa is a development framework (it's actually an umbrella framework which combines three other frameworks, Foundation, AppKit and CoreData).

     These frameworks (Cocoa) define all the objects that are nice to use and interact with the operating system, as well as a number of functions. For example, Cocoa defines things like NSString and NSObject. Cocoa can currently be used with other language bindings, such as python or ruby, and used to be used with Java as well. So, if you were using Cocoa with Java, you would still get an NSString object, but you would call and use it from within a Java application.

     Without linking to one of the Cocoa frameworks, Objective-C comes with only a very basic Object class as a pre-defined root class.

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   • Difference between C and Objective C

     The language C was developed in early 1970s by Dennis Ritchie for the UNIX Operating system. It a general purpose, procedural programming language. The language is used for developing system applications as well as desktop applications. To learn more about C language refer to https://www. geeksforgeeks. org/c-programming-language/

     Objective C was developed in early 1980s by Brad Cox and Tom Love. It is an object-oriented, general purpose language and was created with the vision of providing small talk-style messaging to the C programming language. This language allows the users to define a protocol by declaring the classes and the data members can be made public, private and protected. This language was used at Apple for iOS and OS X operating systems. Swift language was developed at Apple in 2014 to replace this language. But still there are plenty of companies that are maintaining their legacy apps which are written in objective C.

     The main difference in C and Objective C is that C is a procedure programming language which doesn’t support the concepts of objects and classes and Objective C is Object-oriented language which contains the concept of...

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2. www.geeksforgeeks.org › difference-between-c-andDifference between C and Objective C - GeeksforGeeks

   www.geeksforgeeks.org › difference-between-c-and

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   Dec 26, 2020 · The main difference in C and Objective C is that C is a procedure programming language which doesn’t support the concepts of objects and classes and Objective C is Object-oriented language which contains the concept of both procedural and object-oriented programming languages.

3. www.codecademy.com › resources › blogHow Are C, C++, C#, and Objective-C Different? - Codecademy

   www.codecademy.com › resources › blog

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   • The Need For Different Programming Languages
   • What Is The C Programming Language?
   • What Is The C++ Programming Language?
   • What Is The Objective-C Programming Language?
   • What Is The C# Programming Language?
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   Why would someone go through the trouble of creating a new programming language based on another one instead of using the original? First, it makes the new language accessible to the existing language’s user base. Second, it saves developers time since the existing language’s core features don’t need to be recreated from scratch. Third, technology ...

   See full list on codecademy.com

   C is a general-purpose, procedural programming language that was first developed by Dennis Ritchie in 1972. Ritchie created this new programming language based on existing programming languages: ALGOL, BCP, and B. He took features that worked in those languages and combined them to create C. Up to that point, all operating systems were created in a...

   See full list on codecademy.com

   C++ is a general-purpose programming language created by Bjarne Stroustrup in 1985 to extend the C language. It has all of C’s low-level memory manipulation features but added the object-oriented programming paradigm. While the other members of the C family have replaced C in some applications, C++ is the most common replacement for C. In fact, it’...

   See full list on codecademy.com

   Objective-C is a programming language that was developed in 1984 by Brad Cox and Tom Love. They saw the need to add the object-oriented paradigm to the C programming language but used the Smalltalk language as their guide. This led to one of the major differences between this member of the C family and the others in this article. Most of the syntax...

   See full list on codecademy.com

   C#, like all the other children of the C programming language in this article, is an object-oriented, general-purpose language. Microsoft released C# in 2000, adopting features from Java along with C. Instead of being compiled to run on a specific operating system, C# was compiled to run using the .NET common language runtime, much like Java was co...

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   Now you can tell the differences between the programming languages in the C family. It’s a pretty diverse family, but all these languages owe their existence to C. C is still a popular language, especially with embedded systems and places where object-oriented programming isn’t needed. Try our Learn C courseif you’re interested in learning the basi...

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4. builtin.com › objective-cWhat Is Objective C? (Definition, Uses, vs. Swift) | Built In

   builtin.com › objective-c

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   Dec 22, 2022 · Objective C vs. C: What’s the Difference? Syntactically speaking, Objective C is an extension of the popular C programming language. This means knowing C will definitely help you learn Objective C. One of the key differences between Objective C and C is that Objective C has an object-oriented class system not present in C.

5. www.geeksforgeeks.org › what-is-objective-cWhat Is Objective C? (Definition, Uses, vs. Swift ...

   www.geeksforgeeks.org › what-is-objective-c

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   Mar 5, 2024 · Let’s get started. What is Objective C? Objective-C is a general-purpose, object-oriented programming language that was developed in the early 1980s by Brad Cox and Tom Love. Mainly, it is used for software development on Apple’s macOS, iOS (mobile), watchOS, and TVOS platforms.

6. stackoverflow.com › questions › 2445050How different is Objective-C from C++? - Stack Overflow

   stackoverflow.com › questions › 2445050

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   A major difference is that Objective-C is focused on runtime-decisions for dispatching and heavily depends on its runtime library to handle inheritance and polymorphism, while in C++ the focus usually lies on static, compile time, decisions.

7. People also ask

   What is the difference between C and Objective C?

   • The main difference in C and Objective C is that C is a procedure programming language which doesn’t support the concepts of objects and classes and Objective C is Object-oriented language which contains the concept of both procedural and object-oriented programming languages. Difference between C and Objective C:

   Difference between C and Objective C - GeeksforGeeks

   www.geeksforgeeks.org/difference-between-c-and-objective-c/

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   Is Objective C a programming language?

   • Objective C is a general-purpose, object-oriented programming language that’s a superset of C. Objective C has been around since 1980 and became the main language for NeXTSTEP operating system. NeXTSTEP is the system from which Apple derived iOS and OS X. What Is Objective C Used For?

   What Is Objective C? (Definition, Uses, vs. Swift) | Built In

   builtin.com/software-engineering-perspectives/objective-c

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   Should I learn Objective C If I don't know object oriented programming?

   • If you know C but have no experience in object-oriented programming (OOP), you’ll need to learn the object-oriented class system in Objective C. C has been around since 1970 and is the grandmother of many of the most popular programming languages in use today.

   What Is Objective C? (Definition, Uses, vs. Swift) | Built In

   builtin.com/software-engineering-perspectives/objective-c

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   What is Objective C used for?

   • The primary use case for Objective C is building iOS apps and macOS applications. Apple created Swift to make it easier to get started with iOS app development. While Apple still supports Objective C, there aren’t any updates to the language on the horizon.

   What Is Objective C? (Definition, Uses, vs. Swift) | Built In

   builtin.com/software-engineering-perspectives/objective-c

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8. www.theappfounders.com › blog › objective-c-vs-cObjective-C vs. C: Understanding the Evolution of Programming ...

   www.theappfounders.com › blog › objective-c-vs-c

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   May 3, 2024 · Sam Mendes. Share on. Facebook | Linkedin May 3rd, 2024. The C programming language has a long history dating back to the 1970s. It was created by Dennis Ritchie at Bell Labs and was designed for systems programming. Objective-C was created as an extension of C in the early 1980s by Brad Cox.

9. en.wikipedia.org › wiki › Objective-CObjective-C - Wikipedia

   en.wikipedia.org › wiki › Objective-C

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   One notable difference is that Objective-C provides runtime support for reflective features, whereas C++ adds only a small amount of runtime support to C. In Objective-C, an object can be queried about its own properties, e.g., whether it will respond to a certain message.