Thread: Trouble using GOTO with the SWITCH statement!

I suggest that you turn that global variable into a local variable and format your code so that it is easier to read:

Code:

#include <stdio.h>

int main()
{
    int numval = 4;

    printf("\n Numval = %d \n", numval);

    switch (numval)
    {
    case 0:
        {
            printf("\n Case 0 = %d \n\n", numval);
        }
        break;
    case 4:
        {
            printf("\n Case 4 = %d \n\n", numval);
        }
        break;
    case 8:
        {
            printf("\n Case 8 = %d \n\n", numval);
        }
        break;
    case 12:
        {
            printf("\n Case 12 = %d \n", numval);
            printf("\n Both Motors Forward \n");

            if (numval != 4)
            {
                goto case 8;
            }

            if (numval != 8)
            {
                goto case 4;
            }

            if (numval = 12)
            {
                goto case 12;
            }
        }
        break;
    default:
        {
            printf("\n Default = %d \n\n", numval);
        }
        break;
    }

    return 0;
}

Now, I am not entirely sure what is the logic you are trying to implement, and I am not entirely sure if you can use goto on a case label in a switch, but you probably do not need to use goto here, and in fact you should avoid the use of goto.

So, what exactly are you trying to do?

It looks he wants to loop while numVal is 12:

Code:

#include <stdio.h>

int main()
{
    int numval = 4;

    printf("\n Numval = %d \n", numval);

    do {
        switch (numval)
        {
        case 0:
            {
                printf("\n Case 0 = %d \n\n", numval);
            }
            break;
        case 4:
            {
                printf("\n Case 4 = %d \n\n", numval);
            }
            break;
        case 8:
            {
                printf("\n Case 8 = %d \n\n", numval);
            }
            break;
        case 12:
            {
                printf("\n Case 12 = %d \n", numval);
                printf("\n Both Motors Forward \n");
            }
            break;
        default:
            {
                printf("\n Default = %d \n\n", numval);
            }
            break;
        }
    } while (numval == 12);

    return 0;
}

So what are you trying to do?

Skip all the "on line" stuff. What do your sensors need to read, and what happens when they read something? Nothing about frequencies or whatever ... put it into words. What happens with the sensors find something or don't?


Quzah.

Originally Posted by xxJaRxx

Its really hard to explain.. Im programming a buggy to follow a white line on the floor, it has two sensors, left sensor on line is 4, right sensor on line is 8, both on line is 12 and neither on line is 0. Ive made a flowchart and started to write this code but I cant get any further without the goto working or at least something very similar to goto.

The trouble is, if you cannot explain it, you probably do not really know what you are doing. In fact, I know of programmers who explain what they are trying to do to the nearest unsuspecting victim (who may or may not be programmer) in order to better understand what they themselves are trying to do. Oh, and of course if you do not know what you want to do, we cannot really help you either.

Nontheless, I shall give it a try. I suspect that you want to do action X when the left sensor is online, action Y when the right sensor is online, and action Z when both are online. But when both are online, you still want to do actions X and Y. If so, an easy solution is to place actions X and Y (and possibly also Z) in functions, then call these functions depending on what sensors are online (i.e., your switch will come into play).

Code:

while true
    if left and right
        do a thing
    else
    if left and not right
        do this
    else
    if right and not left
        do that
    else
        do another

I'm not really sure why you need goto at all.


Quzah.