View difference between Paste ID: eYeULTX9 and W5xEytbv

 #include <stdio.h>
 
 ///////////////////////////////////////
 // Base
 
 typedef struct _base
 {
    char*(*GetName)(struct _base*);
    char* name;
 } Base;
 
 char* base_get_name(Base* base)
 {
    return base->name;
 }
 
 void base_init(Base* base, char* name)
 {
    base->name = name;
    base->GetName = &base_get_name;
 }
 
 ///////////////////////////////////////
 // Derived
 
 typedef struct
 {
    // by making the parent struct the first data member
    // of the derived struct, a `Derived*` can be cast into
    // a `Base*` for pseudo-polymorphism; however, you lose
    // out on static type checking because of this cast, so
    // an `int*` passed in will cause a crash at runtime
    Base Base;
 } Derived;
 
 char* derived_get_name(Base* derived)
 {
    return "derived";
 }
 
 void derived_init(Derived* derived)
 {
    derived->Base.name = "";
    derived->Base.GetName = &derived_get_name;
 }
 
 //////////////////////////////////////
 // Functions
 
 void PrintName(Base* base)
 {
    printf("%s\n", base->GetName(base));
-   Base* bPtr = &b;
+
-   base_init(bPtr, "base");
+
-   PrintName(bPtr);
+
 {
    Base b;
-   Derived* dPtr = &d;
+   base_init(&b, "base");
-   derived_init(dPtr);
+   PrintName(&b);
 
-   PrintName((Base*)(dPtr));
+
    derived_init(&d);
    PrintName((Base*)(&d));
 
 
    // This would compile (because the cast breaks static
    // type checking), but crash:
    // int i = 40;
    // PrintName((Base*)(&i);
 
    return 0;
 }
 
 // output:
 // base
 // derived