Can I implement a method in structure in C?

Question

I want to implement methods in C language. I know C language doesn't support Object Oriented Programming. But is there a way to do it? Or is it can't be done? Because it need to done by C.

struct student
{
    int name;
    int address;

    void speak() 
    {
        /* code */
    }

};

int main()
{

    //code ..

    student.speak();

}

This is how my code look like.

I'm voting to close this question as off-topic because the OP used no sleuthing prior to asking. — KevinDTimm, Oct 01 '15 at 19:10

score 6 · Accepted Answer · edited Oct 01 '15 at 19:32

6

You may partially emulate this by using pointer to function.

struct student
{
    int name;
    int address;

    void (*speak)();
};

void speak_func() {/*...*/}

int main()
{
  //code ..
  struct student student;
  student.speak = speak_func;

  student.speak();
}

edited Oct 01 '15 at 19:32

alk

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answered Oct 01 '15 at 19:11

Matt

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2

Notice that you won't have a `this` pointer when you use this trick, which renders it mostly useless. – fuz Oct 01 '15 at 19:12
1

@FUZxxl Yes. A programmer should declare and pass it directly if needed. – Matt Oct 01 '15 at 19:13
But this breaks the entire reason why you would use this trick. – fuz Oct 01 '15 at 19:15
@FUZxxl You can supply 'this' so, no, it doesn't. – Rob Oct 01 '15 at 19:16
@FUZxxl It doesn't "break", but it makes things to look really ugly. – Matt Oct 01 '15 at 19:17
@user4419802 -Thank you – Chamin Wickramarathna Oct 01 '15 at 19:51
Additionally, your minimal example calls the function with the other fields of the object uninitialized (although it’s effectively static). – Davislor Oct 01 '15 at 22:45
@FUZxxl Python's OOP needs to pass `this` as the first argument of its "methods". – Matthieu Apr 13 '16 at 16:54

score 2 · Answer 2 · answered Oct 01 '15 at 19:09

2

No, that's not possible. You can do some tricks to get a result that looks similar but I don't recommend them. In C, you would just use a function:

void speak(struct student *student) {
    /* ... */
}

answered Oct 01 '15 at 19:09

fuz

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Your answer is incorrect. Google for "oop in C" where you'll even find a pdf on the subject. I've done this for years myself. – Rob Oct 01 '15 at 19:21
@Rob Where exactly is my answer wrong? – fuz Oct 02 '15 at 15:42

Can I implement a method in structure in C?

2 Answers2