Dynamic jump to label in C

Question

I would like to display the output - numbers 1 to 5, followed by 4-5 infinitely. Is there any way i can pass the value of i(4) instead of the character i in goto1. Or is the

Answer 1

Are you asking for a jump table? If you are using gcc: It has a jump table mechanism.

#include 

int main()
{
    unsigned char data[] = { 1,2,3,4,5,4,5,0 };
    // data to "iterate" over, must be 0-terminated in this example

    void *jump_table[] = { &&L00, &&L01, &&L02, &&L03, &&L04, &&L05 };
    // you should fill this with all 256 possible values when using bytes as p-code

    unsigned char *p = data;

    begin:
        goto *jump_table[ *p ];

    L00:
        return 0; // end app
    L01:
        printf("num %i\n", (int)*p);
        goto next;
    L02:
        printf("num %i\n", (int)*p);
        goto next;
    L03:
        printf("num %i\n", (int)*p);
        goto next;
    L04:
        printf("num %i\n", (int)*p);
        goto next;
    L05:
        printf("num %i\n", (int)*p);
        goto next;
    L06:
    L07:
    // ...
    LFF:
        goto next;

    next:
        ++p;            // advance the data pointer to the next byte
        goto begin;     // start over

    return 0;
}

The pro about this method is that you spare the large switch statement.