How can I access an array created in another function in main without returning it?

Question

First post on StackOverflow. I'm supposed to create a function:

int sumsort(int *a, int *b, int *c)

This function should arrange the 3 values in the memory locations pointed to by a, b, and c in ascending order and also return the sum of the contents of the memory locations a, b, and c.

Here's my function:

 int sumsort(int *a, int *b, int *c) {

    int sum = *a + *b + *c;

    int sorted[] = {*a, *b, *c};

    for (int i = 0; i <= 2; i++) {

       if (sorted[0] > sorted[1]) 

       {
          int temp = sorted[1];
          sorted[1] = sorted[0];
          sorted[0] = temp;
       } // end if
       if (sorted[1] > sorted[2]) 
       {
          int temp2 = sorted[2];
          sorted[2] = sorted[1];
          sorted[1] = temp2;
       } // end if

    } // end for

    return sum;

} // end sumsort function

How can I access the sorted[] array in main? I need to print the 3 variables in ascending order but don't really see how I can do that since the sumsort function has to return the sum and the actual sorting has to happen in the sumsort function too.

I tried creating a new array variable in main and assigning it sorted[] after I call the sumsort function, but that doesn't work because it's out of scope?

You are not allowed to change the signature of `sumsort`? You can't give it a 4th argument? — asimes, Mar 01 '19 at 05:52
Make an array of *pointers* and sort that array according to indirect values — Basile Starynkevitch, Mar 01 '19 at 05:53
Your task is to *swap the contents* of `*a`, `*b` and `*c`. Not creating a new structure which would reference them in order as you did, but simply swapping them. — Ext3h, Mar 01 '19 at 05:58

score 1 · Answer 1 · answered Mar 01 '19 at 05:57

1

You are correct that you cannot access your sorted variable from main. But you don't need to. The point of the function is that it modifies the values pointed by its parameters.

For instance:

int main()
{
    int x = 5, y = 1, z = 3;

    int sum = sumsort(&x, &y, &y);

    // now  x == 1  ,  y == 3  , z == 5
}

This is possible. Inside sumsort you need not to create a new array, but to modify the values pointed by it's paramters.

For instance, if you had to sort just two numbers this is what you would do

void foo(int* a, int *b)
{
    if (*a > *b)
    {
        int temp = *a;
        *a = *b;
        *b = temp;
    }
}

answered Mar 01 '19 at 05:57

bolov

72,283
15
145
224

I see. I don't know why I felt the need to create an array. Thanks! – Professional Grammer Mar 01 '19 at 06:10
You may also want to look at [Simpler way of sorting three numbers](https://stackoverflow.com/questions/4367745/simpler-way-of-sorting-three-numbers) for inspiration. – David C. Rankin Mar 01 '19 at 06:14

score 0 · Answer 2 · answered Mar 01 '19 at 07:56

You can declare sorted[] as global variable outside of main:

int sorted[3];
main()
{
  int a=20, b=15, c=22, sum;
 sum= sumsort(&a,&b,&c);
 printf("%d",sum);
 printf("%d", sorted[0]);
 printf("%d", sorted[1]);
 printf("%d", sorted[2]);

 }

And in your function you can use it as shown below:

 int sumsort(int *a, int *b, int *c) {

 int sum = *a + *b + *c;

 sorted[0] = *a; 
 sorted[1] = *b;
 sorted[2] = *c;
 for (int i = 0; i <= 2; i++) {

   if (sorted[0] > sorted[1]) 

   {
      int temp = sorted[1];
      sorted[1] = sorted[0];
      sorted[0] = temp;
   } // end if
   if (sorted[1] > sorted[2]) 
   {
      int temp2 = sorted[2];
      sorted[2] = sorted[1];
      sorted[1] = temp2;
   } // end if

} // end for

return sum;

} // end sumsort function

You may have to check your sorting logic.

Hope this helps :)

How can I access an array created in another function in main without returning it?

2 Answers2