Question

I’ve got following code fragment and I want to know if it is pure C or it contains some C++ elements. This question stems from the fact that I think it is only C, but some compilers don’t accept the code.

   // User struct derived from FunctionBlock
    struct Function{
        // Inputs
        int codeGenerationIterator;
        int i;
        char* s;
        // Outputs
        // Internal
    };
    void FunctionCall(struct Function *arg){
    }
    void FunctionConstructor(struct Function *arg){
        arg->i=3;
        arg->s="!";
        // Call constructor for all not primitive variables
        // Create struct with first call
        FunctionCall(arg);
    }
    // User type definition
    typedef struct Punto{
        int codeGenerationIterator;
        Function x[3+1];
            Function *x_pointer[3+1];
        double y;
    };
    void PuntoConstructor(struct Punto *arg){
        // Call constructor for all not primitive variables
        for(arg->codeGenerationIterator=0;arg->codeGenerationIterator<=3;arg->codeGenerationIterator++){
            arg->x_pointer[arg->codeGenerationIterator]=&(arg->x[arg->codeGenerationIterator]);
            FunctionConstructor(arg->x_pointer[arg->codeGenerationIterator]);
        }
    }
    // User type definition
    typedef struct Cerchio{
        int codeGenerationIterator;
        double r;
        Punto centro;
            Punto *centro_pointer;
    };
    void CerchioConstructor(struct Cerchio *arg){
        // Call constructor for all not primitive variables
            arg->centro_pointer=&(arg->centro);
        PuntoConstructor(arg->centro_pointer);
    }
    // User type definition
    typedef struct Container{
        int codeGenerationIterator;
        Cerchio circonferenza[10+1];
            Cerchio *circonferenza_pointer[10+1];
    };
    void ContainerConstructor(struct Container *arg){
        // Call constructor for all not primitive variables
        for(arg->codeGenerationIterator=0;arg->codeGenerationIterator<=10;arg->codeGenerationIterator++){
            arg->circonferenza_pointer[arg->codeGenerationIterator]=&(arg->circonferenza[arg->codeGenerationIterator]);
            CerchioConstructor(arg->circonferenza_pointer[arg->codeGenerationIterator]);
        }
    }

    int main(void){

        // Variable definitions
        int codeGenerationIterator;
        int count;
        Punto insiemePunti[50+1];
            Punto *insiemePunti_pointer[50+1];
        Cerchio cerchio;
            Cerchio *cerchio_pointer;
        Container container;
            Container *container_pointer;
        Container containers[11+1];
            Container *containers_pointer[11+1];
        // Call constructor for all not primitive variables
        for(codeGenerationIterator=0;codeGenerationIterator<=50;codeGenerationIterator++){
            insiemePunti_pointer[codeGenerationIterator]=&insiemePunti[codeGenerationIterator];
            PuntoConstructor(insiemePunti_pointer[codeGenerationIterator]);
        }
            cerchio_pointer=&cerchio;
        CerchioConstructor(cerchio_pointer);
            container_pointer=&container;
        ContainerConstructor(container_pointer);
        for(codeGenerationIterator=0;codeGenerationIterator<=11;codeGenerationIterator++){
            containers_pointer[codeGenerationIterator]=&containers[codeGenerationIterator];
            ContainerConstructor(containers_pointer[codeGenerationIterator]);
        }

        container.circonferenza[1].centro.x[0].i=2;
        containers[2].circonferenza[2].centro.x[4].i=2;

    printf("Works!");
    getchar();getchar(); // TODO: delete
    return 0;
    }

As you can see I haven’t use classes or overloading but only simple instructions, structs and some pointers. So, why do some strict C compilers give me an error?

Answer 1

No, this is not valid C. This line:

    Function x[3+1];

lacks the struct keyword, and there’s no typedef struct Function Function; to introduce the type alias you seem to be using.

Also, the use of // comments requires a recent-enough compiler, that syntax wasn’t added to C officially until C99. An older compiler would fail for this reason, too.