======================
   '23 Mar 13 16:24
======================
Written by ~leha2 from
ctrl-c.club. Credit if
shared. Thanks.
======================

Want to use classes in C? You can do it with structs and function pointers!

In your headers:
    struct SomeClass {
        int propertyA;
        float propertyB;

        int (*modifyPropertyA)(struct SomeClass* self, int value);
        void (*free)(struct SomeClass* self);
    };
    
    struct SomeClass* SomeClass_new(int valueA, float valueB);
    int SomeClass_modifyPropertyA(struct SomeClass* self, int value);
    void SomeClass_free(struct SomeClass* self);

And in your sources:
    #include "SomeClass.h"

    struct SomeClass* SomeClass_new(int valueA, float valueB) {
        SomeClass* self = malloc(sizeof(*self)); /* You should check if allocation failed normally */
        self->propertyA = valueA;
        self->propertyB = valueB;
        self->modifyPropertyA = &SomeClass_modifyPropertyA;
        self->free = &SomeClass_free;
        return self;
    }
    
    /* SomeClass modifyPropertyA function here */

    void SomeClass_free(struct SomeClass* self) {
        free(self); /* If you have any other structures inside the class, you should free them too, otherwise you will have a memory leak. */
    }

And to call these functions inside your "class" struct, you do:
    struct SomeClass* class = SomeClass_new(1, 1.0f);

    (class->modifyPropertyA)(class, 2); /* Calling the function pointer */

    (class->free)(class);

You might not want to include class methods in contexts when you need to work with the least memory possible, as they also eat up your bytes.