pointers doubt

[ayoros]

hello friends

i'm trying to generate in an intermediate code (almost C) a function, with labels and gotos and i have this problem with the pointers (maybe i wont never understand pointers).

#include <stdio.h>

int main() {

char *puntRetorno="";
char *point = &puntRetorno;

printf("empezando\n");
puntRetorno="i";
goto ESCRIBIR;


i:
printf("fin\n");
return 0;

ESCRIBIR:
printf("hola\n");
//valorRestorno=0;
goto retorno;

retorno:
printf("Ya casi: %s\n",point);
goto *point;

how can i do to make the pointer *point points to the char puntRetorno has inside?

I've tried so many ways but nothing...

Thank you very much

[whiteflags]

Okay, imagine the flow of a C program: it generally starts at main() and moves from top to bottom. goto changes the flow of the program by moving execution to a labeled line. A label can only be a descriptive tag, so you can't goto a variable, like you were doing with point.

goto does have some uses (particularly if you like single return points) but other than that, the lack of a solid code structure makes things hard to read. Look up what "spaghetti code" means.

You need to rethink whatever you are trying to do.

[dwks]

how can i do to make the pointer *point points to the char puntRetorno has inside?

Assuming you mean, "how can I make point point to puntRetorno" -- you already did that.

char *point = &puntRetorno;

Of course, you didn't do it correctly, but hey. puntRetorno is already a pointer; when you assign something to point it's expecting a pointer; so just use puntRetorno by itself.

char *puntRetorno="";
char *point = puntRetorno;

[ayoros]

Sorry but I think I'm not explaining myself very well...

I need to do that because I'm making a compiler for PHP in a intermediate code that I have to compile then with gcc.

To translate functions to this intermediate code I need to use labels and gotos.

dwks, I have to do: "goto *point" to use this label anytime, can i do that?
I just thought *point could has inside a different string each time i need.

thank you

[Salem]

> char *puntRetorno="";
> char *point = &puntRetorno;
That should be char **point

> goto *point;
This will never work in C, it is a compiled language not an interpreter.

The best you can manage in C is something like this, to turn a keyword into an identifier

#include <stdio.h>
#include <string.h>

/* use a table for large numbers of cases */
int lookup ( const char *s ) {
    if ( strcmp(s,"hello") == 0 ) return 0;
    if ( strcmp(s,"world") == 0 ) return 1;
    return 2;
}

int main()
{
    char    *word = "hello";
    switch ( lookup(word) ) {
        case 0:
            printf("hello\n");
            break;
        case 1:
            printf("world\n");
            break;
        default:
            printf("Huh?\n");
            break;
    }
    
    return 0;
}

[Brad0407]

Con mi compiler, no puedo usar una variable con "goto". Intenta:

#define point i

Pero, este no compilara:

printf("Ya casi: %s\n",point);

No pienso que tu puedas hacer que tu estas intentando hacer. Quizas en un idioma diferente.

[brewbuck]

> goto *point;
This will never work in C, it is a compiled language not an interpreter.

That has nothing to do with it. There's no reason such a feature couldn't easily exist in C, it just doesn't. In fact, the GCC compiler does allow you to do this (with almost, if not exactly, the same syntax as used here), as an extension to the C language. You "take the address" of a label, and then goto that address. Quite useful for implementing large jump tables, which are rampant in lots of system-level software like the Linux kernel.

But obviously, as it is non-standard, it isn't something to rely on for typical programming tasks.