Assign function return to char array variable

Question

I have a function called "retornaMaior" which returns a char array, and I want to assign this return to a new variable like:

char variable[] = retornaMaior();

Is there any way to do this? If there is, how can I do that?

I was thinking about declaring the "variable" as a global like "cartas_jogo" but I don't know if it's right.

Code below:

char cartas_jogo[] = "4567QJKA23";
char naipes_jogo[] = "ZCEO";
char carta_retorno[2];

int retornaIndice(char carta)
{
    int a = 0;
    int retorno = 0;
    for (a=0; a<strlen(cartas_jogo); a++)
    {
        if (carta==cartas_jogo[a])
        {
            retorno = a;
        }
    }
    return retorno;
}

char *retornaMaior(char *cartas, const char carta_comp)
{
    int posCartaComp = retornaIndice(carta_comp);
    int a = 0;
    int posMaior = 0;
    int tem = 0;
    int posA = 0;
    for (a=0; a<6; a+=2)
    {
        int posCarta = retornaIndice(cartas[a]);
        if (tem == 0)
        {
            if (posCarta>posCartaComp)
            {
                posMaior = posCarta;
                posA = a;
                tem = 1;
            }
        }
        else
        {
            if (posCarta<posMaior)
            {
                if (posCarta>posCartaComp)
                {
                    posMaior = posCarta;
                    posA = a;
                }
            }
        }
    }
    carta_retorno[0] = cartas_jogo[posMaior];
    posA++;
    carta_retorno[1] = cartas[posA];
    if (tem==0)
    {
       carta_retorno[0] = '0';
       carta_retorno[1] = '0';
    }
    return carta_retorno;
}

In C you cannot return arrays. You merely can return the pointer to the first element of an array. That's actually what you are doing in the retornaMaior function. — Jabberwocky
– Jabberwocky, Commented May 12, 2014 at 17:07
Variable carta_retorno is global, so there's nothing really that you need to do (besides removing the useless return carta_retorno statement). — barak manos
– barak manos, Commented May 12, 2014 at 17:36
You can create an array and pass it to the function, and have the function modify it. That way, you don't have to worry about returning anything at all. — Crowman
– Crowman, Commented May 12, 2014 at 17:44

Mahonri Moriancumer · Accepted Answer · 2014-05-12 17:31:46Z

3

char variable[] = retornaMaior();

Probably won't work. Instead:

char *variable = retornaMaior();

Which can still be addressed as an array:

printf("%c\n", variable[1]);

Within the 'retornaMaior()' function, you will need to put the value returned into memory that can be returned. Using the global variable 'carta_retorno' will probably work; but there is a better way.

Another option would be to allocate some 'heap' memory to the return value. To do this, move 'carta_retorno' from global storage, and move it inside the 'retornaMaior()' function:

char carta_retorno[2];              // ---

char *retornaMaior(char *cartas, const char carta_comp)
   {
   int posCartaComp = retornaIndice(carta_comp);
   int a = 0;
   int posMaior = 0;
   int tem = 0;
   int posA = 0;

   char *carta_retorno = malloc(2);   // +++

As indicated by 'staticx', it is important to ensure that malloc() succeeded:

   if(NULL == carta_retorno)
      ...

Now, the 'retornaMaior()' function will return the result in allocated memory (rather than using global storage).

Don't forget that the caller to 'cp=retornaMaior()' needs to call 'free(cp)' when the return value is no longer needed.

edited May 12, 2014 at 17:31

answered May 12, 2014 at 17:17

Mahonri Moriancumer

6,0132 gold badges20 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

user2591612 Over a year ago

Always check the return value of malloc also.

Collectives™ on Stack Overflow

Assign function return to char array variable

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related